Worksheet tab name

[blainepenn]

Sometimes when I rename a tab for a worksheet, it, it adds the
following: .xls]
in front of the name. For example, I had a tab named "EmployeeInfo"
and I renamed it to "EmployeeDataEntry" (without the quotes). When I
hit <enter>, Excel automatically added .xls] so that the name now reads
".xls]EmployeeDataEntry".

I cannot rename it now, without getting an error message stating that I
entered an invalid name. I am not trying to enter a name with invalid
characters - just what you see above.

Any ideas why Excel is doing this, and what I can do to keep it from
doing this?

Thanks!

BTW, using Excel 2003 SP1.