It's fine for someone to bump their thread after a fair amount of time has passed without a response. "Fiar" IMO being once every 12 hours. It's usually those who bump their thread every hour who piss others off.
However doing do four or so times in a row isn't ideal. If no one wishes to respond it's either because they cannot help, or (for whatever reason - good or bad) don't want to help you/reply. I would have understood this well before having to bump my thread on so many occasions. If anything, any responses I'd receive are likely to be of angry ones.