[Koha] need help

hi i am a student who work on OPAC for my collage library but i still cant ever install koha properly and can work on it if somebody can help me when i install the KOHA there are some modul cant be installed and when i type localhost on my server it apper 500 error waht is it and it even can conect to my server please help me --------------------------------- Yahoo! Messenger with Voice. Make PC-to-Phone Calls to the US (and 30+ countries) for 2¢/min or less.