hey there,
i have exactly the same problem.
computers are in the subcollection based on the OU and the computers show up there, program is displayed on the advertisements for the collection.
the computers also get the notification that the program will be installed within 15 minutes (which seems to fail, but this is another topic =) )
i created the package for firefox as described in the tutorial i found on this forum (great tut btw).
which logs (client or server) do i have to look at? i test sccm 2007r2 with my windows 7 ultimate 32 bit workstation.
thanks & greets,
soomon