Now, your question will have to be dealt with at many levels Sailor...
First of all, the Pakistan Army, though untrained to stand up to such unconventional fighting tactics is a thoroughly professional unit and I have no doubts in my mind that with a little bit of will and training they will be able to stand up easily to the rag-tag militia of the Taliban. The West has given them a lot of aid recently and will continue to do so in the foreseeable future, but there are a variety of reasons why this is not happening.
To try and understand those reasons you have to go back in History.
Starting from 1947 when Pakistan was created, you will notice that it has been getting into trouble with all its neighbours including us Indians. First, it was the issue of Kashmir and as it went on, they kept finding various other reasons. They fought multiple wars with us over that issue. And, history bears testament to the fact that it was they who were the aggressors and not us (check any neutral source that you like to verify this)...
Then, when Zia-ul-Haq came to power he noticed that the country wasn't exactly binding together due to the ethnic and cultural differences that were prevalent and he needed a common factor using which he could bind the country together. This he found easily under the banner of "Islam". He rallied the country under the banner of Islam in an attempt to unite all the different factions. And, very conveniently, at this time the Soviets also invaded Afghanistan, another friendly country to the West.
The Americans seemed very interested in this and wanted to use this as a proxy war against the Soviets to try and deal a defeat (atleast a moral defeat if not a military defeat) to the Soviets. To do this, of course, they needed Pakistan's help without whom all of this would not be possible.
So, they started funding the ISI (Pakistan's Intelligence Agency) which in turn would fund the rag-tag militia from all over the world which had assembled to "save a brother Muslim country from outside interference" or to "Claim back Muslim Land". A lot of the footsoldiers of this military were Pakistanis who were indoctrinated in their numerous Madarasas. At the same time, Zia undertook a total Islamization of Pakistan starting from the bottom up wherein every level of bureaucracy and society would be Islamised.
These included the Army, Bureaucracy, General Society etc. He wanted Pakistan to be a completely Islamic society where everything they did would be in the name of Islam and for Allah. They wanted to be torch-bearers of the Islamic world at large. So, Zia went ahead with this plan. I mean, where did it hurt him ??? It pleased the Americans due to the anti-Soviet footsoldiers, it helped make Pakistan the centre of the Islamic world and it also helped unite the different factions in his own country.
He noticed no immediate fallacy with this plan and he went ahead with it. Implementing the plan even included doctoring their educational system to portray some glaring lies and inaccuracies which were being fed to children from the school level just to achieve what Zia wanted to Achieve.
Hence, with his entire policies, the Islamisation of Pakistan had truly begun from the early 80s.
Now, this was all fine until the Soviets were defeated or were at the verge of defeat. After that, Pakistan needed to find a way to deal with all those youth who were fighting in Afghanistan so far, but after the defeat of the Soviets were essentially "unemployed". All these unemployed youth knew only about radical Islam and knew nothing else so they couldn't be employed in the conventional fields.'
So, Pakistan began looking east. He found India as a ripe target and indoctrinated into these Pakistani youth that big bully India was usurping Islamic Land (Kashmir) and that as the torchbearers of the Islamic World, Pakistan had to stand upto India and deny them that land. If you see the figures that record terrorism and infiltration in the valley, you will notice that they suddenly spiked up or started around the time that the Soviets were defeated in Afghanistan. Before that there were no significant incidents of Terror or infiltration in the valley. They just started around the time when the Soviets were defeated.
This is a clear indication that the youth who became free from Afghanistan were slowly being funneled into India. But, sending them into India was not enough for Pakistan. It wouldn't give "employment" to all their youth.
So, what they did was they supported a group of these highly indoctrinated youth led by a chap called Mullah Omar and they called themselves the Taliban. The Taliban were secretly supported by the ISI and sent off to devour on Afghanistan because the ISI realised that having such a large numer of indoctrinated youth in the country was not good for stability and they had to be given some other work to concentrate on and some other land to use their "Sharia" on. So, they pointed them toward Afghanistan and gave them funds and asked them to go and "chew" on that.
The rest, as they say, is History. The Taliban took over Afghanistan and spread anarchy all over that country with whatever laws they wanted to implement. It was basically like their puritanical society which they had formed on the basis of Islam. Everything thus was hunky dory during the 1990s as the Taliban kept themselves occupied with their activities in Afghanistan.
But, then 9/11 happened and America noticed the threat that Al-Qaida and Taliban would pose to it, even though they were far away. So, they invaded Afghanistan and all the Taliban went running back to "mummy" (ISI / Pakistan).
Now, the situation in Pakistan was also Islamically Charged, the result of the policies that were implemented by Zia ul Haq about 2 decades ago. They believed themselves to be descendants of Arabs, torchbearers of the Islamic World, the bearers of the only Islamic Bomb etc. So, the people in the tribal areas immediately supported the Taliban and made them their guests. They had a safe haven to go around in and they were not threatened. So, they made this their home.
At the same time, the radicalisation of the Army and defence forces was also almost complete. By this time, the radical officers who were inducted during the time of Zia ul Haq had also crossed the Brigadier level and were slowly but surely approaching the General and Lt. General levels in the Armed forces. So, on the whole, they were well and truly on their way to becoming an "Islamic Army" or "Radicalised Army" whichever way you want to refer to it.
This radicalised army refused and still to a large extent refuses to take on the Taliban because they consider them their "Muslim Brothers" who have been fighting for a just cause. Some from the Army even went ahead and joined the Taliban.
Now, you have a situation in Pakistan where a lot of the Generals and Lt. Generals are still not radicalised since they were from before the time of Zia ul Haq. But, a lot of the officers from below them are from Zia's time and they have a radical streak to them. So, if the General orders something, the lower officers might not carry it out to the last word. So, essentially, the Generals are seeing the rug pulled out from right under their feet by the Islamic Fundamentalists in a literal sense...
I think from here on, you can put one and one together and see where we are heading...
Also, Pakistan was created on the funda of Hated for India. So, they see India as the mortal enemy and not one with whom they want to do deals. So, for them as far as India is concerned, its more than just "religion". It's a very personal thing.
So, even if there are Muslims from the higher echelons of power who will try and negotiate with Pakistan and try and put some sense into their heads, I doubt it will work at such a late stage because there will not be ground support for India or any other non-Islamic power trying to go in there to clean up the mess.
I've tried to be as true to my knowledge as possible while writing this explanation. If you guys see any discrepancies, please intimate to me and I'll be happy to correct them.