The problem arises with the interaction with Fermilab's ups/upd products. If you have a FermiRedHat (FRH) 5.n distribution but have one of the newer Linux Kernals installed ups "thinks" that you are running FRH6.n and will install products with the ups flavor "Linux+2.2". This is becoming common since we can't yet supply D0 code for the FRH6.n flavors but the newer machines *must* have the newer kernals to run.
If you install the Linux+2.2 of the newest version of ups, for example, but are running FRH5.n the program will core dump and you won't be able to do much of anything.
I have put a "ups hints" page onto the web with instructions on: