telerik menu breaks in asp.net 3.5

[giani]

i created an application in asp.net 3.5 and using telerik 3.5.   my menu looks nice and everything was fine. 
i added global.asax file to set up some sessions on on start and prerequest and now my meny breaks and seems that html is not rendering. 

is there a work around so telerik always works and renders? 

[Schlurk]

Have your changes only affected the RadMenu, and if so - what particular changes did you do in terms of page rendering etc.?