I entered your error message into Help in xl2007 and got the explanation. I
did the same in xl2002 and got nothing so perhaps not explained in earlier
versions so here is a copy from xl2007 Help.
Why does "Cannot shift objects off sheet" appear when I hide columns or rows?
Symptoms
When you are trying to hide columns or rows, an error message informs you
that Microsoft Office Excel cannot shift objects off the worksheet.
Cause
This issue usually occurs when the following conditions are true:
Objects such as cell comments have been entered in cells toward the end of
the worksheet grid. An amount of columns or rows that is equal to or larger
than the amount of columns or rows between the left border of the object and
the last column (column XFD) or row (row number 1048576) on the worksheet
cannot be hidden.
The option Do not move or size with cells is selected in the Format <object
name> dialog box. This option is selected by default.
For example, if you included a cell comment in cell XFC1, and Do not move or
size with cells is selected, the message appears when you try to hide three
or more columns anywhere in the worksheet between the first column and the
column that contains the left border of the cell comment.
The same issue can occur for rows, although it will not be as common because
of the large row limit in Microsoft Office Excel 2007, which makes it less
likely that you have positioned objects at the very end of the worksheet.
Note It is important to understand that the issue may also occur when an
object is further away from the end and you try to hide any total amount of
columns and rows that is equal to or larger than the amount of columns and
rows between the left border of the object and the last column or row on the
worksheet.
Resolution
If the object is a cell comment, select the cell that contains the comment.
Tip If the object is toward the end of the worksheet, you can quickly go to
the last cell in a row or column. Press END, and then press the RIGHT ARROW
key or the DOWN ARROW key. To go to the last cell on the worksheet that
contains data or formatting, click CTRL+END.
Right-click the selected cell or range of cells, and then click Show/Hide
Comments.
Move the pointer to the border of the object until the pointer turns to a
four-pointed arrow, and then click the border.
On the Home tab, in the Cells group, click Format, and then click Format
<object name>.
On the Properties tab, under Object positioning, click Move and size with
cells, and then click OK.
If you want to hide the cell comment again, right-click the cell, and then
click Hide Comment.
Repeat steps 1 through 6 for each object that causes the issue to occur.
