To install simply put the utx files that are in the textures(v2.0) map into the textures
folder of ut2003 (normally it's X:\UT2003\Textures, were X is your harddisk)and put the
Titaniumpack.upl into the system folder (X:\UT2003\System).Then you must copy the following 
lines to the Xplayers.int (also located in the system map, you can open it with wordpad
or something):

BotSI="Name:  $!LV3R|Age:   N/A|Race:  Titanium AI||Data:|Made of titanium and finished with a nice lay of silver. This beauty will kill every single moving thing in the arena...||"
BotTI="Name:  ']['!t@N!u]V[-300-]|Age:   N/A|Race:  Titanium AI||Data:|Once scientist discovered this new form of titanium they inmediatly started a project called Titanium 300...||"
BotVI="Name:  V!p3R|Age:   N/A|Race:  Titanium AI||Data:|Made of light titanium and driven by a 700pk/hp engine from the viper gts-r, makes this guy a fast killing machine.||"
BotLI="Name:  L!gH'][3n!nG|Age:   N/A|Race:  Titanium AI||Data:|No place to hide, no place to go...to fight, not a chance u win against this speedy fella.||"
BotFL="Name:  Fl(@)$H|Age:   N/A|Race:  Titanium AI||Data:|Once a great warrior created by man to fight the skaarj. Now he's updated with titanium.||"
AlienMaleTI="Name:  Wh!']['3 (@DD3r)|Age:   unknown|Race:  Gen Mo'Kai(Geneticly produced)||Data:|A creation by mad scientists. They cloned an alien slave and injected titanium cells into it. After the experiment it seemed that the alien his skin became stronger, more armored and was still very flexible...the scientists called the experiment "Flex-Ti" (flexible titanium).||"

When you've done all this right the skins should work perfectly :D