That won't help a bit, Ian.
If UBB lacks memberslist.cgi, then you haven't actually set the right path to your Members directory. (There can never not be a memberslist.cgi in any Members directory, ever, period.)
Once you have the paths right in vars_config, when you visit the control panel, you should *NOT* get put into initial setup mode (assuming that the flag in vars_config that mentions being in initial setup mode isn't set - it will be obvious if hand-editing vars_config).