apt-get update fail

Sorry if this has been posted before but I could not find it searching the forums. When I enter apt-get update I always get:

Err SUN Backtrack Linux Repository pwnsauce/multiverse Translation-en_US
Could not resolve 'archive.offensive-security.com'
Reading package lists... Done
W: Failed to fetch http://archive.offensive-security.co...ce/Release.gpg Could not resolve 'archive.offensive-security.com'

I know its not my internet connection because I downloaded backtrack 4 final on the same connection. I believe its just a settings issue. I am running backtrack in virtualbox on windows 7. Thanks in advance for any help.

Try starting the networking service on BT first.
If this is not the case then keep trying. It just worked for me.