VBA: maximum number of sheets

Hi,
I receive an error message when I'm creating multiple sheets with this code:

ActiveWorkbook.Sheets("Report").Copy _
After:=ActiveWorkbook.Sheets("Report")

The error message is:

Run-Time Error '1004'
Copy method of worksheet class failed.

This happens when I have copied 230 sheets. Is it a limit of the number of sheets generated or the limit is related to the size of the workbook?

I tried to execute this code into the loop but without success.
nsheets = nsheets + 1
If nsheets = 50 Then
ActiveWorkbook.Save
nsheets = 0
End If

Many thanks in advance for your kind help.

Regards,

Giovanni