"You do not have permission to release a document"

On a Navision with SQL2000, I have created custom roles for a user, and am trying to apply security filters wherever possible. While trying to post something, I get a message thats says “You do not have permission to release a document” I dint find any help on this! I know this is not directly related to assigning permissions to tables. Please let me know how to get rid of this. I need to apply permissions using custom roles & security filters. Also, if anyone knows where to find more info on ‘Using Security Filters’; please let me know. Thanks.