The 'The package <blah> can't be opened' dialog has at the end:
Press <return> to try again
[ Retry ] [ < Reboot > ]
Reboot is by default selected.
(FC4-re0429.0, ppc, GUI)
It's also getting I/O error on a CD that passes mediacheck. Blah.
Note that clicking on 'Retry' actually calls the reboot code path.
Fixed the button ordering back. The original bug was about text mode and I
didn't notice or I would have just closed it ;)