Okay...I have tried everything I can think of to get XOOPS installed. I didn't have this problem years ago when I did it.
When I go thru the Configuration Check it reports back that MySQL extension Failed.
I have tried MySQL versions 5.1.28 and 4.1.22 - neither worked. I have tried 2 different computers - didn't work. 1 of them is running MySQL 5.1.28 and another app is connecting to MySQL.
If I go ahead and click Next when it gets to step 5/11 - the page fails. I ran the phpinfo() and I cannot find anything that says anything about MySQL. I don't know - I'm at a loss. Someone please help me figure this out! I have tried an older version of XOOPS - that didn't work. I used SQLYog to ensure that root had full access to all tables - even created a table - that didn't work. Ran thru the MySQL instance configuration several times - nothing. Tried unremarking the .dll line in php.ini - didn't work. I'm at a loss.

I found a solution!!!!

go to this website and follow it step by step...

http://www.virtech.org/phpbb3/viewtopic.php?f=7&t=112&p=355

I have a problem with SBS 2003 as well.
Clean install of SBS 2003.
Clean install of MySQL and PHP, following many guides (including virtech.org)
Can create and access db at MySQL prompt.
Can run phpinfo from web directory and see the MySQLi section, but MySQL extension fails at step three (before db connection).
I've setup many XOOPS webs, but cannot get past this problem... any ideas?

Problem solved:
After the patient support of a friend, who prompted me to repeat each step of the installation process, I have discoverd that the MySQLi extension cannot be used as a substitute for the MySQL extension on an Intel box running SBS2003.
When I loaded the proper extension in the php.ini file everything worked as advertised,
duh!

thanks for all the well intentioned emails.