Not vital/important for alpha-testing but a glance through the message 
showed...

   The R listed isn't the R-2.5.0 that was added as a test for 5.0 (of
   course our R users will no doubt be expecting 2.6.0 soon (released in
   October)

   I see no obvious reference to the yum installonlyn plugin though I
   suppose it might be hidden in one of the other yum packages.  If not I
   can offer you the trivial srpm we use...

Attempting to rsync over the 5rolling currently results in:

   rsync: send_files failed to open "/5rolling/i386/yum-conf-LQ-BWW" (in
    scientific): Permission denied (13)

Sadly I'm likely to be unable to test the alphs much in the next few days, 
but I will try...

  -- Jon