I have got the roster installed but I get this message " Could not find guild for server. You need to load your guild first and make sure you finished configuration". I have done some searching around but could not find anything that was in detail of what I should do next. So my question is at this point what do I need to do? Please help me on this. Thanks!

You need ot make sure that you have downloaded Guild Profiler and Character Profiler and used them in game to create the character profiler.lua that you will find in the WOW/WTF/ACCOUNT/SAVEDVARIABLES/ folder.

Upload that using the admin password for the site and you should be all set

hope this helps