Has anyone noticed their installation of GSP hanging on v2.5? I just upgraded my site and the site runs fine for a while but thyen becomes unavailable? There is nothing patrticulary running on the server (eg processor and memory both quiet). If I restart IIS its fine again (until it dissappears) I havem't run any kind of synchronise so i'm a bit confused - it feels like something is using all the iis worker threads but im really guessing here.
any ideas anyone?

There was no error log just a hanging browser.

I figured out the problem though, I have other sites on my web server that need to use v2.5 of the framework, I run GSP on Windows Home Server which runs IIS6. What I had to do was create a new app pool and then configure my GSP virtual directory to use that app pool and finally alter the GSP virtual diretory to use v4 of the framework.
In essence IIS6 wont bother checking if you configure different virtual directories to use different versions of the framework within the same app pool. When the first request hits a website it fires up the app pool to use whatever framework version that particular virtual directory (or the root) is configured to use. As soon as another request comes in to a virtual directory configured to use a different version of the framework within the same app pool it will kill the web server.

To fix this problem you need to make sure that in IIS6, all virtual directories that share the same app pool use the same framework version.

The admin guide says you need to switch the framework version on the virtual directory. This is corrrect provided you have nothing else running on your webserver (specifically no other virtual directories sharing the same app pool as GSP but requiring different versions of the framework)

Sorry this is long winded but hopefully it will help someone out in the future.