Problem with adding new sheet

Hi,

A part of the macro I wrote adds a new sheet to the active workbook. Until now, the code was working fine, but today I encountered the error message "That Command cannot be used on multiple selections", while trying to run the simple code:

Sheets.add

Please note that the workbook is not protected, and multiple sheets are not selected. I have also tried this:

ActiveWorkbook.Sheets.add

and this:

MyWorkbook.activate
ActiveWorkbook.Sheets.add

but none works.

I have realized that this error happens only when the other part of the macro runs the following code:

ActiveWorkbook.SaveCopyAs

So when the SaveCopyAs code has not been run, I don't encounter any problem with adding sheets.

I cannot understand why this error happens, because before even when the code SaveCopyAs was ran I did not have any problem with adding sheets, and since then I have not changed anything about this part of the code where it adds new sheets.

Somewhere on the web somebody suggests using the following code:

Worksheets.Item(1).Select

before the add code, but it doesn't solve my problem. (I assume because my problem is not that multiple sheets are selected, because in the title bar I see no [Grouped] sign.)

Note that I am using Excel 2010.

P.S: After running the SaveCopyAs code mentioned above, I also cannot add sheets manually via Excel.