your License Key will work on both OS, but you'll get support only for the OS version you purchased. Price is only £16.95 . Don't buy the AppStore version, as it's tied to Apple.
1MB is more than enough to surf on the site comfortably ; his issue was likely about something else (extremely bad ping or packet losses come to mind).
Is there an option to delete a frame ?? Or Cut it and paste it in the end ? Select all the biped parts, then select all the Keys on the timeline after the frame you want to "delete", then move them 1 frame to the left. You might need to redo that with the vertical root part (it's usually ...
So if you wait for the "Connection lost" message, and then select Rep and click the "Give Rep" button, does it freeze as well ? Or does it freeze only you click "Ok" ?