Apache2 install problem: apt-get can not find/fetch libpq5 pkg from http://us.archive.ubuntu.com

While i had not hand any problem installing RoR on my Dell Ub 8.10 box
previously, when I tried to do the same on my HP Pavilion Ub 8.10 box
today (4/14), during the installation of Apache2 (via apt-get or
Synaptic pkg manager) I got the following error msgs:

After this operation, 6263kB of additional disk space will be used.
Do you want to continue [Y/n]? Y
Err http://us.archive.ubuntu.com intrepid-updates/main libpq5
  404 Not Found [IP: 80]
Failed to fetch http://us.archive.ubuntu.com/ubuntu/pool/main/p/postgresql-8.3/libpq5_8.3.6-0ubuntu8.10_amd64.deb
404 Not Found [IP: 80]
E: Unable to fetch some archives, maybe run apt-get update or try with

Any idea why the above lib is missing?