Hi, I'm getting this 500 error at install also and have spent two days on it so far going through all the forum threads and trying every advised solution. I've set 777 on /config & /tmp, made sure mod_security isn't enabled, set a .htaccess file as well as adding AddHandler and AddType directives for both php and html to the default site conf but nothing has worked so far.
I see quite a few have just continued through with the install and apparently all is well. I'm a little reluctant to do so but I guess if it's just a red herring then that's ok? Although I'd rather have a clean install process myself.