Install Alien

[Gunawan]

Hi there,
I have search on alternate cd dan found alien*.deb and many other file that 
maybe require when installing alien.
I would like to know why I can not use apt-get install alien to install it 
from alternate cd?
And so with mono, I would like to install mono and alternate cd provide many 
binary of mono.

I knew that to get source online is better but my issue is some ubuntu boxes 
are offline.
Regards,
Gunawan