Excel Ad in cannot Append

[M H]

Hi all,
I have a strange problem where I have been appending some excel tables, organized by year, into to a single table in mysql (table 1). On one such file the append add-in simply would not work (it won't even load the screen that has the column mapping). There is no error message given, except for "Cannot find column 33"

I thought it may have been an error with the excel file, but I was able to append the Excel table with the error message to another temporary table in SQL (table 2). Shortly after I tried appending previously effective Excel tables back into mysql (table 1) and it would still not work. That rules out Excel tables issues.

Does anyone have any suggestions?

Thanks.