It's been a long time, but this sounds familiar. I seem to remember that this was a bug and there was a patch for it. Radical FX used to be available from Rayflect and when RD started including it, the release version still had the serial number checking in it. There was a fix, but I can't remember the details. Try applying the patches. Good Luck, Eric Winemiller Digital Carvers Guild Freeware and commercial 3D extensions http://www.digitalcarversguild.com

Eric Winemiller
Digital Carvers Guild
Carrara and LightWave plug-ins