Connection Problem

[JJET7504]

I am new to vnc and was hoping that I could get some help with my problem.

  I downloaded vnc on my computer at home as well as my boss on his computer
at his house. He is running window xp profession and I have the xp home.  He
is able to access my computer and is able to call me into his computer but I
can not get through to his.  When I pull up VNC Viewer to put his IP address
my is in there, my IP comes up automatically and I have to delete it and put
his in (not sure if this might be the cause). Once I have his in and I try to
connect I get the following everytime.....unable to connect to host -
connection timed out (10060).   I'm not very computer savy so any help is very
much appreciated.

  Many thanks....Tara