Hi Brett,
A friend of mine encountered this about a week ago. I haven't been using OACS for months now, but using web CVS I also got a similar findings as yours. I suggested to my friend to check his etc/config.tcl it might be already old. Can you try a newer etc/config.tcl? He said after a few mins he was able to resolve it and also he had to purge is browser's cache. I am not sure the exact details how he resolved it, he just said thanks and was able to install. Anyway good luck, I am sure others will reply to help.
