OK, so I have this problem as well. The only difference is that the other poster seemed to indicate that it happened to them sporadically.
It happens to me every single time.
I have been testing CBSUBS for over a month now on a staging site and it has worked flawlessly.
I just imported a new set of users and a new set of content (Sections, Categories, articles) and when I went to test the site, all content works fine, users work fine but I can't go into the CBsubs plugin and I get the error message.
I have tried with and without www
I have tried with different users.
I have applied some of the fixes here (but not all, it only happened 1/2 hour ago for the first time). No dice.
Tomorrow I am going to:
1) Create a new user
2) Clone the site and load a backup I made
3) pre-content/user merge
4) Clone another site and try an intermediate backup
Hopefully, one of the backups will work and it'll let me narrow it down to when the plugin got screwed up.
Luckily, I made no file changes (no plugins/ modules/components) So I can replicate the site as many times as I want and even bring it back to the original.
FIY:
CB gives me another error. After running the plugin tools I got this error (in black) when checking the plugin DB consistency
CB plugin "CB JCal pro events": no database or no database description.
CB plugin "CB JCal pro mini-calendar": no database or no database description.
CB plugin "Acajoom CB Plugin": no database or no database description.
The 3 plugins above came out in black. Yet, the DB is fine, I checked. I am not sure about DB description but the DB is there and so are the entries for all 3 of them.
FYI again:
Joomla 1.5.18
PHP Built on: Linux 2.6.18-028stab068.9 #1 SMP Tue Mar 30 17:22:31 MSD 2010 i686
Database Version: 5.0.90-community
Database Collation: utf8_general_ci
PHP Version: 5.2.13
Web Server: Apache/2.2.15 (Unix) mod_ssl/2.2.15 OpenSSL/0.9.8e-fips-rhel5 mod_bwlimited/1.4
Web Server to PHP interface: cgi
Joomla! Version: Joomla! 1.5.15 Stable [ Wojmamni Ama Mamni ] 05-November-2009 04:00 GMT
User Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.3) Gecko/20100401 Firefox/3.6.3