any success? Did you look into the documentation: http://docs.openhab.org/addons/bindings/tradfri/readme.html? There exists an additional parameter for the port. I assume the host parameter only expects an IP address or hostname without any port given.
The odd thing is that my Tradfri Gateway works just fine with my “old” OpenHab setup on Ubuntu, but won’t work with my “new” OpenHabian install (everything else works fine so far - I can see my other network devices, I can switch my WeMo plug, it’s all good! - only Tradfri is problematic).
At first it was “uninitialized”; then it initialized, but now it reports status “OFFLINE - COMMUNICATION_ERROR”.
I checked my Ubuntu install again just to be sure, and it still works.