That error can because by a bunch of things but it's usually some kind of corruption. First try to compact and repair your database. If that doesn't work update your virus scanner and check for that. You may need to reinstall Microsoft office. It could even the Windows registry corruption so you might have to reinstall Windows. Basically something is broken on your system.

I got this error too. You can resolve it by open a new empty access. Import your database, everything. Check option at the last tab. If the problem still occurs, make a copy of the problematic form. Name it to something else. Then delete the problematic form. Now, rename your copy to the original name.
If this doesnt work, see Richards answer.

Thanks for the tips, Jan. :)