Hi all!

Im fairly new to Vulnerability scanning. Im using Backtrack 5 r2 running on a virtualbox i uninstalled nessus 4 and installed the 5th version.
I tried scanning targets in my local network and found that the scans give incomplete results.
My main pc is a macbook pro running snow leopard, i installed nessus on it and did a self scann it gave me a bunch of critical, high and medium vulns, however when i did the same scan with the Backtrack box i found none of this vulns and found only 5 info and 1 medium.
So i scanned the backtrack box using the nessus scanner inside it and again found a big pile of vulns in int from mysql to some flash and java holes.

My question is: Why scanning targets in the network gives incomplete information whilst scanning the localhost gives the complete info?
How can i configure the scan so that i can obtain info on all my network computers?

BTW the same happens with openvas... Could it be my network configuration? is it a router issue?