No Admin Page After Login

[quickpick]

I do volunteer work for an organization and didn't upgrade Coppermine since version 1.4.18. I noticed couple of "deprecated" notices on the top of the gallery and decided to upgrade to 1.5.20 (latest version). I also noticed that after I login as administrator I'm unable to actually have the administrator panel or link to it. When I type in "admin.php" I get "You don't have permission to access this page." Upgrading to version 1.5.20 didn't seem to resolve that issue. I now reverted back to 1.4.18. Any advise on fixing this issue? I have Rainy Day theme if it's any help, in case it's a theme issue.

[Jeff Bailey]

1.4.x is no longer supported so please try to upgrade again and try it with the default curve theme.

If you continue to have problems please post a link to your site.
http://forum.coppermine-gallery.net/index.php/topic,55415.msg270616.html#msg270616