does the client not boot up at all for you? try downloading the unscripted version. I seem to have errors here and there but it always seems to workout once I close and reboot client. try opening the osrs client via RM, the select the other osrs option on RM once client is opened.
issue resolved:
download the unscripted version rather then the MACos or windows, upon doing that make sure you have the Runescape client downloaded, if your running MAC make sure you follow the steps listed in the OP about MACos.
I am having the same issue where it tells me “Cannot locate...