My iPhone 4 is currently pissing me off by showing this message every 10 minutes or so (sometimes not for a while, sometimes every few minutes). It basically thinks there's something connected to the dock connector (there isn't).

It just happened again while I was typing this (I'm not typing this on the iPhone, it's sitting on my desk). The error cuts out the audio as well because obviously it thinks it's connected to a dock or speakers etc. - but the audio comes back after 10 seconds or so.

I've tried a Restore, and I've tried running paper back and forwards over the connector pins in case there was lint in there or something (there wasn't).

Do you think it's worth the hassle buying a can of compressed air and blasting the connectors in case there is a tiny grain of sand or something that's bridging two pins? (not that I've been near a beach in this amazing Auckland weather).

Or should I just bite the bullet and begin the lengthy repair process with Vodafone?