joking-down, I'll send it to you ASAP. Do you only need privatedelete.cgi? (I think that's all there is of the delete script. There are many other files in the hack though, and some modification of core ubb files is necessary.)
Kinda weird that this never worked and no one even bothered to mention it in the docs.
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.