IIS7: A process serving application pool 'YYYYY' suffered a fatal communication error with the Windows Process Activation Service

We're running a 32-bit Windows server 2008 with an IIS version of 7.
We're attempting to publish an asp.net 4.0 webapp and so far our attempts have only yielded a few warnings in the serverlog without even stopping the 4.0 application pool

A process serving application pool 'ASP.NET v4.0' suffered a fatal communication error with the Windows Process Activation Service. The process id was '1904'. The data field contains the error number.

The application is running under a 4.0 app-pool and under the default website.
We've also got some older .asp's running flawlessly.
Even when attempting to publish a barren (read. only 1 line of text) .aspx-file it failed miserably... We've since long run out of ideas on what to do so any form of input would be appreciated...

Solution 1:

Make sure that each Application Pool in IIS, under Advanced Settings has Enable 32 bit Applications set to True

Solution 2:

I was debugging the problem for the better part of the day and when I was close to burning the building I discovered the Process Monitor tool from Sysinternals.

Set it to monitor w3wp.exe and check last events before it exits after you fire a request in the browser. Hope that helps further readers.