Select Table comes up a second time for some worksheets

Problem running a mailmerge with an Excel workbook. Some of the worksheets
work, other worksheets bring up the select table a second time and it is
blank. There are worksheets for all 12 months. March, May, July, September
and November have this problem. The other months are fine. We can select
the 'May 05$' in the select table box, then it comes back a second time
blank. When we select the 'January 05$' table, the mailmerge is successful.

Why do some of the worksheets come up with the select table box a second time?

I contacted the originator of the excel workbook and here's what he said:

I created all the worksheets the same way. by copying the spreadsheet in the
tab labeled "List A-Odd Months" and pasted it into the actual month's tab.

Any ideas would be appreciated.

"Ellen" wrote:

Problem running a mailmerge with an Excel workbook. Some of the worksheets
work, other worksheets bring up the select table a second time and it is
blank. There are worksheets for all 12 months. March, May, July, September
and November have this problem. The other months are fine. We can select
the 'May 05$' in the select table box, then it comes back a second time
blank. When we select the 'January 05$' table, the mailmerge is successful.

Why do some of the worksheets come up with the select table box a second time?