Merge many avi files ConvertXtoDVD4

Windows XP Athalon 64
When I select a number of avi files to merge to a tilelset, some are out of order, and in fact will change order if every time I reenter the editor.
If I just select 2 or 3, the last one is always placed second.

Trying to convert about 50 separate avi files which make up a complete set on a home video camera

thanks