I can think of two reasons that you might be having issues:

1) if ADO is issueing the command as a temp. stored procedure or using the sp_executesql system stored procedure, the temp table will be released when the stored procedure terminates.

2) You may be being bit by connection pooling or OLEDB's session pooling.

I'd suggest that you do all of your working within a stored procedure instead of making multiple calls to the database.

-Mike