I tried all the options specified in the link: http://stackoverflow.com/questions/1332207/uninitialized-constant-mysqlcompatmysqlres-using-mms2r-gem but nothing is working.
I have an iMac with Snow Leopard installed. I am currently using the mysql gem version 2.7 and I checked that ruby was 64 bit but I am unsure if the mysql gem is 64 bit as well(or does that matter?). I do know that my local mysql server is 64 bit although I am currently trying to migrate to remote mysql server.