The RHS pbo's in the 506th pack go into their corresponding RHS folders, AFTER the RHS mod has been put in place. Otherwise, the RHS installation will overwrite them, and they'll show up as missing. I know this has caused issue for other people as well, when the order wasn't done correctly. If that still doesn't solve your issue, you may wish to look at your RPT file, from your attempted connecting to the server, and see what mods it's trying to pull up that are missing.