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

Bad new for all of us. I restored a back up I took today before starting my work with users and content and I am experiencing the same issue not only on the same browser, but on other browsers and even a couple of laptops and a Mac that I have never used with this site.

Ball back in your court. We had very high hopes for this software, but considering the fact that no one here seem to be able to fix the issue (or even know what's due to) we may have to go with a different ACL at the last minute. Something I really didn't want to do.

However, if you guys at Joomlopolis would like to take a crack at this I can supply you with a copy of the site on a dedicated server of your choice o9r I can even package it up for you. Just as long as this gets resolved.

By all means: it's CB SUBS. I have been doing this for 5 years and I have never seen this error.

Let me know . I'll do a few more tests (I have another, earlier backup I can try) but my deadline is bust.

Another day, same error message.

I need to know how to properly unistall CBSUBS and if there is something more than just delete the plugins.

I am going to do several tests and one of them involves getting rid of CBSubs.

By the way, I saw Joobi mentioned in the thread. Amazingly, I had just installed joobi setup not long before encountering this issue because we needed a way to track newsletters.

So I just uininstalled it and the error is still there, but since Jsetup also has an ACL component to it (which I have not installed though) it would make sense as the culprit of the error. How about the other folks? Do you have Jsetup? If you do, then we know what's causing this.

In any event, I am now proceeding on several parallel tracks trying to get some ACL in place. CBSUBS or anything that will do the job.

I'll keep you posted but I wouldn't mind seeing a direct response.

I think I found what the problem is, at least as far as I am concerned.
Since I am very anal retentive when it comes to web development, I backup the site each time I install anything major. So I was able to install and configure 3 sites with the following attributes:

#1 Joomla with CBSubs
#2 Joomla with CBSUBS and Joobi's Jinstall
#3 Joomla with CBsubs, Joobi;'s Jinstall and some extra content work I did in PPhpMyAdmin (WHich I thought could have caused this since I manually edited some CB tables)

The breakpoint is #2, the Jinstall installation. I should point out that since I installed it I didn't even set it up. Not even opened it. I was planning to first Upgrade Acajoom to Jnews and then install Jbounce (for tracking the newsletters, the reason I am installing Jinstall at all).

So just installing Jinstall (but not the relative components) for me was enough to encounter the error.

I'd be curious to know if the others experiencing this issue also have Jinstall or some other ACL program.

Thank you.