Development on diagrams is rather slow at the moment, but it is still actively used and maintained.  The best places to get help are (1) on the #diagrams IRC channel on Freenode (you probably won't get an immediate response, but any messages will definitely be seen and will get responded to eventually if you stick around), (2) the mailing list as others pointed out.  We try to be a helpful bunch and would love to help you get diagrams working for you.