custom query var NOT working on a plain permalink: http://10.8.10.9/?page_id=1774/?location=968&floor=1

I think you should really try to make the permalinks work on your server. It seldom fails. Have you checked all your server settings are correct, and have you visited the permalink page after updating, so that the cache is flushed?

Otherwise you would have to have http://10.8.10.9/?page_id=1774&location=968&floor=1 and that would work too.

I’d really try to get the permalink issue fixed first though. It should work on any server really.