Too much data in access database?

Hello All,
I have created an access database for my HR department at work but I get error# in each field on the database. Once I [x] out of the database and then go back to it, everything seems to work fine. Someone told me this may be due to the large amount of data in my database. If this is the problem, then what should I do? I would like to be able to keep all data in one database for easy lookup. Please help if you can.
Thanks so much.
