Don't understand firewall message

Hello Group:
My system:
Router Linksys BEFSX41
Desktop - Win XP Pro SP3 32 bit, Deerfield Visnetic software firewall
Laptop - Win 7 pro 64 bit

I just bought the laptop,plugged it into the router, and Win 7 set up
the networking without any input from me.
My desktop has an IP address of
The two connect just fine.
But now I am constantly getting messages from the firewall on the
desktop about an inbound TCP connection attempt:
Source (? the router or the laptop) on port 50193
Destination: 192.16831.151 (my desktop) on port 445

I would appreciate an explanation of what may be going on, and advice
if I should block or allow it.

Maybe I need to give my laptop an IP address. My old one was XP
machine with IP

Many thanks.