Hello
my gallery(v1.5.3) worked fine , but for about 2 weeks when the admin uploads files via advanced mode the "Security Error" message appears.
Security permission on Album folder and it's sub folders is 7 5 5 and Simple mode works fine. My host admin says nothing has been changed on the server.
I really don't have any idea and really appreciate your clues about this problem.
Post a link to your Coppermine - it is required for support. See the link "Board Rules" above.
Follow the guidelines in your document package - "Upload Troubleshooting" and "Asking for Support on Upload Issues".
No one will want to help (or be able to efficiently help) until you do all of the above.