Can you try it on another computer?
If so, do multiple databases have the same issue?
If not, then I suspect that you might have an issue with Access, and might need to re-install it on your computer (and make sure that you have all patches applied).
The other thing to consider (as I have seen it corrupt a lot of databases) is:
- Do you have multiple users using this database?
- Are they all on the same version of Access?
- Have you split the database and given everyone their own copy of the front-end?