Can Only Access Front Desk's Shared Files by Using Certain Credentials

We have 5 workstations in our office. The back end of our database is held in a shared folder on the front desk computer. From my computer, I can access this folder by using the front desk computer's admin credentials. However, I have set up another account on that computer called Database, which is only allowed to read the database folder.

The other 3 people in the office have a less robust front end for the database, and I would like them to be able to access the shared folder by using the Database account's credentials. When entering the credentials for that account, it simply gives me a bad logon error, as if the useame or password is wrong (it's not).

What setting(s) should I change to solve this?

Most computers ruing Windows 7 Home. Front desk ruing Windows 8.1 Thanks.