It means you have something in the last row(s) and cannot shift
the rows down.
Use Ctrl+End to find the last cell, which is the intersection
of the last row with content, and the last column with content.
Spaces are content, and formulas are content as are empty strings.
More information in
http://www.mvps.org/dmcritchie/excel/lastcell.htm
Some people try to hide calculation formulas in an out of the
way place -- a very bad thing to do.
If you try to copy an entire sheet and paste that into another
spreadsheet below row 1 it will not fit.
