3006 A parser error has occurred.

I made some changes today on my website and suddenly I got this warning: Event Code 3006 A parser error has ocured in the event viwer log. My website stoped to function giving a runtime error.
It took me a while to work this around but this is what solved my problems:

1. Stop your server
2. Go to Windows\Microsoft.NET\Framework\v2.0.50...\Temporary ASP.NET Files\
3. Delete everything inside this folder
4. Restart your server and than it should work

I hope this will work for you to.