These may be on the disk and it may be set to use the disk in your sources
as previously mentioned. If that is the case, then it will ask for the CD
in preference to downloading from the repositories. By changing to sources
and deselecting using the CD you can avoid this message. I have found that
using the CD is only helpful at the beginning because as packages get
upgraded the CD versio0n falls behind and needs to be upgraded anyway.

Build-essential includes a bunch of packages that are necessary from
compiling source code. Some apps such as VMWare or VirtualBox may require
them as part of their dependencies since it needs to compile modules to work
with the kernel. DKMS is similar as it works to compile kernel modules
dynamically. I am not sure what the perl modules are used for, but most libs
are dependencies for other packages.

Will there be any more Austin Powers movies?