Plugins for Documentation Subscribers - Blank Scr

Well, I subscribe Docs to support and get access to others Cb Tools. So I ask you, Do I need some extra config to make this plugins work?
I tried CB ProfileBook 1.2 RC2 and CB ProfileGallery version 1.2 RC2, at back end fine, at front end, blank screen, nothing. Source too.
maybe I have this problems with others plugins.
Old version work fine.
I dig on Jomlapolis Faqs, Forum, and nothing
I tried everything, disable all other plugins
At server's log, just favicon missing.
I activate Joomla! Debug, nothing, PHP memory limit to 64
I follow Kyle's signature, nothing.

Why Cb is become so difficult?
I'm afraid with next Cb version.
But I'll try anything to go forward with Cb.

Any clue to solve this problems?

My System:
CB 1.2.1
Linux s2000.websitewelcome.com 2.6.28.9
PHP 5.2.9
Mysql 5.1.30
Joomla! 1.5.14
memory_limit 64M
permissions OK

maybe you didnt publish the tabs?

i would take advantage of the documentation and read it.

also the cb gallery package has very detailed documentation - did you read it?

Have you tried with a default Joomla template? Are there any error messages on your server logs?

First of all. Thanks for the fast response.

Let me include more information.

Yes, I published the tab.
Yes, I tried with other template (rhuk_milkyway)
Yes, I read docs (it just explain basic operation, no troubles)
I tried with 2 different servers, Apache and IIS.
I tested with fresh install, it works.
I uninstall and install again CB, and it works.

But, Joomla! is no more a small CMS, and after a site is working for years, I can't do a fresh install and recompose all site easy.
Reinstall CB is a trouble too, I have some developed plugins and adjusts that I'll need to reinstall, maybe I miss a lot.
I upgraded "all" Joomla!'s files to 1.5.14, and I made "expert upgrade" to CB 1.2.1. Do I miss some?
Worth, I have 6 sites with CB and this problem too.

Something is conflicting with "Doc Subscribers plugins" with "expert upgrade". I have no idea where is this, and I have no error log, nothing, according my first description, but, reading at forum, I have seen a lot of "blank screen" problems, so, is it a chronic cb problem after expert upgrade?

Maybe it's a basic problem, but the bigger problem is that it only occurs with cb plugin, and without error, code, and source (html result).
Maybe "experts" upgrade miss something.

I'm not a programmer, but I can read and understand code, but not enough to solve this.
Please, give me a clue to find and solve this problem.

Thanks Nant and Rapunzl
I am impressed with your promptness.

well, there is obviously something happening with our specific environment.

It might help to look at error logs of web server.