I had a strange problem when I was upgrading from Rogero 4.21 to Rogero 4.30 where the PS3 thought I was on system update 4.42. Because of this it thought Rogero's 4.30 was outdated, it was all fine once I installed Rogero's 3.55 cfw again, though. Bleh, such a monotonous process, hopefully I won't have to update again anytime soon. But yeah, I'd say install 3.55 cfw now and then install Rebug or whatever you're looking to install, if that's what your problem is.
Derp, this is also in the wrong forum, just realized that now. You may wanna post this in the PS3 Help & Support forums - at least, if I didn't help you out there.