Problem with receiving updates and software

Mon Aug 4 00:07:57 UTC 2008

I have Ubuntu 6.10 -
The system has been working fine until recently, when I went to receive 
my updates, I received and error  message saying "page not found".  Also 
the same message when trying to upgrade to 7.0, this also happens when 
using the "add/remove" software feature under Applications.
How can these problems be resolved?
My e-mail address is:    behnkej at bellsouth.net
Thank You for a quick response,

Jim Behnke