Error 1 Handles clause requires a WithEvents variable defined in the containing type or one of its base types.

 I can't remember changing anything significant to my project, but now whichever aspx page I open, I get the error:
 
Error    1    Handles clause requires a WithEvents variable defined in the containing type or one of its base types.    
 
There is no masterpage/stylesheets so every page is individual and I just can't understand why it's coming up with this error whenever I try to debug any page!?
 
Thanks
 

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