From that, we can't tell much, if anything.
When you get problems like this, start by Googling the error message:
Google: "A process serving application pool 'DefaultAppPool' exceeded time limits during shut down."[
^]
The first hit is MSDN:
http://support2.microsoft.com/kb/2634635[
^] which tlaks about the error, why you get it and what you can do.
It's not that helpful in this specific case, because basically what it says is "debug your application" - but it does suggest some things that may be wrong with your code.
Certainly, we can do no more!