Strange Debian sources.list quirk?

[Gaijin]

	Hi folks,

	Upgraded to Debian Lenny from a scratch Shane Etch disk, and
voila!  A slew of SpeakUP modified kernels.  I apt-got the docs first to
see what was what, and commented out the "deb cdrom:" in
/etc/apt/sources.list, and all the kernels disappeared.  Uncommented the
line again, and thank God the list reappeared.  Anyone have a clue what
the story behind this is?

			Michael