Try with below step, hope this resolve issue.
1. Stop IIS. Remove temporary asp.net files. Start IIS again.
2. If #1 doesn't resolve the issue, check the permissions on the Temporary asp.net files and give the appropriate permission as per the user under which your app pool is running.
3. Try changing the app pool identity from Local System to some specific user. Though the error code is different as per this thread: http://forums.iis.net/t/1159648.aspx?Compiler+Error+Message+The+compiler+failed+with+error+code+128+
4. If none of the above work, you may need to start checking logs in Process Monitor as per the above referenced thread.