Data module create fails on one computer

I'm not sure which is the appropriate newsgroup - hope this one is ok.

I have an application that is behaving strangely.On two computers there is
no problem. On a third computer the application fails when it tries to
create the data module (I've managed to trace it that far.) I have several
other applications that use the same database, and a similar data module.
They work fine on all three computers.

Any ideas on tracking this down?