haymann, which version of SME are you running right now that you are getting 502 updates available? Also, have you added extra repositories?
I'm running 7.0 at one site and the max amount of updates it gives me is 242, but I reckon I'd rather walk in there with a shiny new version 7.1 and just update the system from there...
It was 7.0 and I have SME Server - addons; SME Server - os; SME Server - updates; and SME Server - dungog as repositories.
I ended up rebooting the server and when it came back up (thank goodness

) I tried using yum from the CLI. It kept failing a dependancy check for OpenSSH so I went back to server-manager -> Software Installer and de-selected the two OpenSSH updates. The update took awhile, but was successful. I still haven't gotten OpenSSH to update.
Server-manager now reports that I am using SME 7.1
I don't know where all of the "extra" updates came from... I am using Dansguardian, SARG, Awstats, and remoteuseraccess from dungog; perhaps that is why there were more??