We have a few records in our database that won't allow data to be entered.

We can call up the record and edit any of its fields that already have data, but if we go to a blank field, it won't allow us to do anything.

99% of the other records in the database are fine.

Any thoughts on what is going on here?

Do you have Admin privileges ?

Sounds potentially like data corruption.

Backup the file. Then try recovering the file, saving a compressed copy, and both recovering and saving compressed copy.

If problems persist start looking for known-good backups of the file.