Secured DB with default workgroup

[Ben]

I have a created a secured db that i want to use with user's default
workgroup files. I have added the admin user to my fulldatausers group with
appropriate permissions. During my tests, if i log in without using the
secured workgroup file, i get a message saying i dont have permissions to
read the data in the tables. However, if i log in with the admin account
using the secured workgroup file it works.

Any ideas why? ive even tested giving the admin user full rights on the
tables and it still doesnt work.

thanks.