Spring RTS Engine

Hey, i've tried searching but it rathr hard to search for such a problem, but me and a friend have been trying to play spring.
We've got the same client version and spring version, both running XTA v9 gold and using a base map that comes with it so theres no problems there, but it wont start properly, we've tried with and without bots, but it still crashes.
My game will load and ill be waiting for him to join, but his game will start then go blackscreen and revert back to the battle screen.
theres no error message and i don't get told that he's disconnected.
He says it tries to connect, and after 30seconds it closes, so it sounds like he's not able to connect to me?
but we've tried with and without firewalls and anti-virus, but to no avail.
Any obvious cause you can think of?
Cheers

Do you have a router? Try enabling NAT traversal when hosting.

yeah i do, Its one of them Bthomehubs. Where would i go about enabling NAT Traversal?
I cant remember with the NATs very well, isnt that linked to the firewall somehow?

ive sorted the NAT out, got the ports done. But it still wont go through. My friend has a screenie, it says

Warning too many unit categories 33 missed all
initializing map features
generating trees
parsing unit icons
Creating unit textures
reading estimate path costs
creating sky
Spring 0.75b2

any ideas what the warning means?

That warning is unimportant, it's a mod error and the mod was probably tested with it.

oh right okay then.
But it still wont let us connect.
We've opened the right ports not and we've been able to play loads of other games online togther fine.
Any other ideas?