David, i see in your screenshot that you've tried to create openfire-service.vmoptions file. Have you tried to put same memory values into this file and then run the service version? Works for me.
As about adminstrator thing. This is how Windows 7+ (and maybe also Vista) works. You can't simply edit files in Program Files, even if you have full admin rights. It always asks for confirmation with UAC dialog. As Openfire has to read/write files in the Program Files/Openfire/conf, logs and embedded-db folder if using internal database, that's why you have to run launcher with Run as admin command. Same for all programs storing their configuration in Program Files.
