This one is really for application support teams. All I ask is that you understand how your app works before you blame the database. For instance, if a user is unable to save a project to a database in your application, you should know and understand the workflow and the security model that is in place. You should know if your app handles security for accessing the database or if that is done at the database level. You should know if you are using Active Directory, some other LDAP, or local accounts for access. You should know if the application interfaces with the database with a service account, or if every user needs to have database level access. You should know what the pre reqs are, in the app, for saving a project. What fields does the end user have to have filled out or completed before that can occur. You should know if your app is dependent or integrated with another app and if so you should understand all of the above for the second application as well. I do not think that is too much to ask and I certainly do not think it is too much to ask that you have your app configured to connect to the correct database before coming down and asking the DBA to take a very granular look at permissions of users that are and are not able to save these projects.
And yes, I did have an application person come down and ask me to look at object level permissions for some users and compare them, they were the same. And yes he had the app pointed at a database other than the one that he had me investigating. So please, do not waste my time. Know your app, know the workflow, know how to check your database connection, and know the security model.