Are the updates from your .htaccess file being reflected in the phpinfo page? or are they being ignored?
I think this has to be the problem, so I'd probably go to the hosting company and see if there is another way to change these values.
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.