[Serusers] About Serweb installation

[Guty]

I'm running my SER on  a debian 3.1.
I've installed (i think so) all necesary stuff to run SER whit mysql support 
and serweb interface.
when I try to acces it, i receive the following message:

Warning: main(DB.php): failed to open stream: No such file or directory in 
/home/gustavo/serweb/html/main_prepend.php on line 38

Fatal error: main(): Failed opening required 'DB.php' 
(include_path='.:/usr/share/php:/usr/share/pear') in 
/home/gustavo/serweb/html/main_prepend.php on line 38


I'll preciate if anyone could help me....
(as you could see, I'm new to all this stuff... )
Thank you.....