Mar 09, 2009 03:51 PM|Segundo|LINK
If you register the user controls in the web.config.. you can use inside any subfolder ... it should work.
The error you are having can be originated because the page is not getting the last info refreshed from the web.config... to solve this issue, you can generate your project again... perhaps you should also close the page at the visual studio y open it again...
sometimes, this issue is solved closing and reopening again the visual studio.
Any doubt, post your comment.