Hints
From Sage CRM Knowledge Base
Forcing an update of a cached JavaScript file in IIS
Ref: http://www.hanselman.com/blog/ForcingAnUpdateOfACachedJavaScriptFileInIIS.aspx
IIS 404 messages but directory browsing is possible.
Chances are that ASP.Net was set as prohibited in IIS. Re enable to fix.
Application pool Idle timeout set to 43200 (30 days)