Application has stopped working B1 V9

Hi

I have wrote a report for a customer for B1 V9 which takes some time to run as it runs lots of queries

With the customers data, running it locally it takes about 1 minute on my notebook

On the customers network they keep getting a message about the application has stopped working at various points in the program and doesn't finish

I update the message bar but wonder if it could be the form I am displaying which I am not updating which could be causing problems

We are both running B1 V9 PL8

Just wondered if anyone has had a similar problem and can suggest anything please ?

Thanks

Andy