It doesn't really sound like an Excel-specific problem. And your description doesn't really go very far in describing the situation, what you've tried so far; all you're telling us is that you're having trouble and get an error message with a couple of bits of info in it, neither one of which is Excel specific.
So all we can really do is general stuff.
Have you tried shutting down, re-booting, and going back to the task in question, "copying am Excel Chart to Publisher"?
Are you able to copy other sections of the Excel workbook to Publisher? (i.e., is it something specifically "Chart" related?)