A couple of things
Have you compacted the db?
Have you tried opening the NewRecord form directly - i.e. not from the switchboard - if so, does it open OK
If you get the error (and I guess even if your don't) have you looked at any code that may exist in the form (initially look at open, load and current event)
Finally I notice you say it is a .mdb file. If you look on the web, there are a number of reported issues with running 2003 on windows 7.
Here is one solution you can try
and another - basically suggesting the same thing
If you are running 2000 or earlier this link says it is not compatible with Win 7
However there are plenty who argue it will run, compatible or not