OMG…I hate this one.
Most of the times when you’re using textbox references (like: ‘Reportitems!Textbox33.Value‘) and when I think you press ‘Delete’ on certain cells, VS automatically renews the textbox-numbers. So things get messed up.
So…check if any of your report items are referencing non-existing textbox items, non-existing paramters or fields that are not in existing dataset scope.
Funny thing is that when you start deleting other report items (of which you think they work properly), VS somehow makes up his mind by giving you a decent error message: