This is a bug in the way the SUU was created by Dell. Due to the internal dates that were used during the creation of SUU, the timeout came up a bit early. Its a benign message, SUU 6.5.1 is the current version. 6.5.3 will most likely be posted sometime next week. 
Probably a silly question, but why, when I run updates from my Server Updates (version 6.5.1) dvd am I told that it's over 120 days old and to visit dell to get a newer version but when I get to Dell, it wants to download the very same version with the same revision date as the one I'm trying to use? Is it just telling me that SOME of the components are newer?   Thanks! KBeau
Dell Server Update Utility