What pointshop are you using?
Pointshop 1 (by Adam Burton, aka _Undefined, this is a free version)?
Pointshop 2 (by Kamshak, this is a paid version)?
As far as I know neither, pointshop restricts viewing by rank (at least not by default). If you have a custom one however, then it's quite possible that it does this by default. As for why it's allowing you in admin and superadmin, but not owner, it's because owner is not a default Garry's Mod rank. Vanilla GMod only has three ranks, user, admin, and superadmin. As such, most scripts that restrict access based on rank will use these three ranks. If your owner rank doesn't inherit from admin or superadmin, the script has no way of knowing you should have access.
To put it simply, you're doing it wrong. Sorry to break it to you, but Garry's Mod is not built for advanced inheritance systems. All your groups (just another word for rank) should be in your inheritance chain, and you should try to follow Garry's Mod's "conventions" as much as you can. That means that superadmin should be
the highest rank on your server. I'm not sure why you wish to have SeniorAdmin, Manager, and Owner. If it's because of the naming, you shouldn't be using the groups as tags.
To fix your issue, make sure you inherit from admin or superadmin.
