Being mostly a newbie myself, I was dissappointed with the Redhat package manager since it only seemed to deal (graphically at least) with the rpms that came on the 3 redhat cds. When I downloaded other applications as rpms, I found the same thing as you when I "right clicked and then chose to install the package." It seemed to start, but never finished.
I started a shell prompt (alt-ctrl-F1 then do alt-ctrl-f7 to get back) and then had to log in as root. THen I installed the package, using the rpm command. I found that earlier attempts to install them had failed. I found that I needed to be logged in as root, and some packages lacked other pre-requisite packages (dependencies.)
Using the package manager thing that redhat provides just seemed to bring up the same packages. No new ones were in the listing anywhere.
Best of luck,
btw, I have just about given up on linux. back to micro$loth, I guess for me.