Problem inserting new record

I developed a small program one year ago. The purpose of this program (VBA) is to extract the information from Email in Outlook and store it in the MS-Access database. The program works smoothly previously until recently, when new mail arriving at the Outlook, the program was not able to extract the data and store it in database, after some investigation, i found out the that current database hold 6377 records or equivalent to 100MB of size. No matter how i try, the program just couldn't insert the new information into the DB, then i tried to backup my current database, and replace the Database with a fresh copy of database with empty data inside. Guess wat, the program can work again!

Can any expert out there tell me what is going on !!!??? Thanks alot for help.

You could try compacting the database to see if it can reclaim any space. You should be able to store more than100M in an Access database.

Could it be due to the Reduced-functionality mode that prohibit the insertion of record?

Have you tried to INSERT a record from the MS Access environment? What happens in that case? If that fails what is the error that it displays? Also which version of MS Access do you use?
I have used larger databases MS Access DBs with no problem.