Hi,
First point - I have not installed this tool before. But i have read through the documentation from your link. It seems the Openmaint has pre-requisite softwares that need to be available in the server. I have done installation of those pre-requisites before - for example, PostgreSQL, Alfresco (community version). What I can do is to follow the documentation guide to setup Openmaint. I have a good expertise on Linux flavours, so i can overcome any dependency issues while installation. By the way, which Linux distribution you are using - Ubuntu ?