Nessus not scanning network on OS X

[Tom Thomas]

A bit of house keeping, thanks for all the answers regarding getting 
nessus running on an xserve, its all set and starting as expected, 
etc... from your suggestions I figured it out.

Now nessus starts and will scan its own ip address but will not scan 
any other ip address on any subnet. This is the same issue I am having 
on the other Apple machine and for the life of me I am stumped.

There are two common factors OS X and me, so if its me making a mistake 
can I get some suggestions on where to look?

Thank you