I have recently been getting a lot of error when trying to download something... The problem from what I am seeing is that a certain program needs for example libgmp2 but I already got libgmp3 so why dosent apt-get just download it?

My /etc/apt/sources.list:
Code:
# See sources.list(5) for more information, especialy
# Remember that you can only use http, ftp or file URIs
# CDROMs are managed through the apt-cdrom tool.
#Debian
deb ftp://ftp.debian.org/debian unstable main contrib non-free
deb-src ftp://ftp.debian.org/debian unstable main contrib non-free

#Debian Non-US
deb http://non-us.debian.org/ unstable/non-US main contrib non-free
deb-src http://non-us.debian.org/ unstable/non-US main contrib non-free

#Debian security updates
deb ftp://security.debian.org/debian-security stable/updates main contrib non-free
deb-src ftp://security.debian.org/debian-security stable/updates main contrib non-free

#deb http://people.debian.org/~branden/ sid/i386/
#deb http://download.us.kde.org/pub/kde/stable/3.0.3/Debian ./ 
# KDE 3.0.3

#Ximian
deb http://red-carpet.ximian.com/debian stable main