There are results on Google, from as new as a week or two ago.
You're not in FAST/alltheweb though, which really surprises me. FAST easily handles UBBs, even without spider friendly URLs.
That sorta tells me that the spiders just aren't interested for now... suggest submitting to both sites, and getting more people to link in, then pointing spiders that the linking sites...
Donate to UBBDev today to help aid in Operational, Server and Script Maintenance, and Development costs.
Please also see our parent organization VNC Web Services if you're in the need of a new UBB.threads Install or Upgrade, Site/Server Migrations, or Security and Coding Services.