I've had something similar happen.
I have no idea if my 'solution' actually fixed it or if it
was just a coincidence.
But it "seemed" that even though I "selected" the worksheet.
the "Active" sheet remained the same.
i added the line: worksheets("Maria").activate (for example)
after the Worksheets("Maria").select statement, and it seems to have fixed it!

Like I said, it may not even be the problem...
give it a shot..