IMP w/ MySQL question

[alexus]

Hi

i'm trying to install IMP and it requires horde to be installed

after "installing" of horde i'm geting


Fatal error: Failed opening required 'db_mysql.inc'
(include_path='/usr/local/apache/phplib:.') in
/usr/local/apache/phplib-7.2c/php/prepend.php3 on line 19

in line 19 it says

require($_PHPLIB["libdir"] . "db_mysql.inc");  /* Change this to match your
database. */

first of all.. i guess i'm missin what is mysql has to do with web email
(imp) and where do i read on that in imp/horder/phplib? i didn't find
anything on mysql in any of those.. which tables needs to be created? and
etc etc etc

i've tryed to fill out db_mysql.inc i put all my settings like host, dbname,
userid, password it still won't work and i'm geting same error