Got my first real Weborder the other day

even though only 5% of all products are visible to public...
But for some reason when the person paid with Paypal, the order went thru twice.
Both orders were status: pending, but we got a notification from Paypal of a successful payment that corresponded to the 2nd order (1 minute interval between the2)
Got a mail telling me of the error, and I see this inside the log :
ERROR checkPaypalIps: Error with REMOTE IP ADDRESS = .
not a typo, the IP address shown is just a dot, .
My website is hosted by a friend who is a linux guru, and site is behind firewalls and other things (not sure what he's done but it is secured...). The fix is probably a combination of change of configuration and possibly some rule changes in the firewall or on the hosting side of things, but does anyone know what I/he should do, in this case?
thank you !
Edit 1) Sorry, i posted in the wrong forum. Moved it now ...
Edit 2) Looks like issue is 'known'
2) IP address issues
When the IPN is received, we check that it comes from PayPal. Sometimes, this check fails even though the IP comes from PayPal, we are at the moment investigating this issue.