Lotus 123 millennium macro is shut down by windows 2000

[Guest_imported]

I am running a Lotus 123 (millennium) macro which calls up data files, performs calculations and merges files. It runs fine in "step" mode or when only one file is called. But when several files are run sequentially 123 shuts down and I get the error message "The program has generated an error and will be shut down by windows". And it does! Is this a timing problem? I have tried adding a wait statement but no luck.

Any thoughts????