Larry,

I'm not aware of any Excel limitation. My guess is you're trying to
Select the hidden worksheet. Example: If Sheet1 is hidden, something
like this will cause an error.

Sheet1.Select
Range("A1") = 1

Instead use:

Sheet1.Range("A1") = 1
or
Worksheets("Sheet1").Range("A1") = 1

I prefer the first syntax so the code doesn't need to change if the
sheet tab name changes. Example: if the tab name for "Sheet1" is
changed to "First Sheet", then Sheet1.Range("A1") would still work but
Worksheets("Sheet1") would need to be changed to Worksheets("First
Sheet").

Very seldom do you ever need to select or activate the object to work
with it. If you use the macro recorder though, it will often select
everything because that is what you're doing while recording. Result
is hard to read and unecessary code.

Just a guess at what might be causing the problems. If no help, try
posting some of the problem code.

HTH,
Steve Hieb