I think I've got your solution.
####Require_Encrypted_Auth = !-ioFTPD !*
####Require_Encrypted_Data = !-ioFTPD !*
These 2 fields MUST be defined so just remove the leading #'s. If you don't care if anyone uses SSL or not just use "= !*" somewhere. In fact it's already there on the line. Commenting them out entirely obviously does bad things though. I'll fix requiring this to be defined in 6.4 which is coming out soon, but just uncomment the lines for now