Error message : You must select a shape
 

Running Excel 2007. After I clicked on the Page Layout and Page Break
Preview buttons and then back to the Normal button on the View tab, I
started getting this error message whenever I pressed one of the arrow
keys to move the active cell. Ctrl-Home did nothing. Clearing the
message just cleared the message. Press an arrow key and it would
return. I could change the active cell by clicking on a different
cell. It was present on all sheets in that workbook.

As a test, I loaded another workbook. That one didn't have the
problem. When I closed that workbook, the problem had cleared up in
the first workbook.

Can anyone tell me what I did and how to clear it?