In reply to Kimono:
iPhone connectors can be iffy. We had one that came with a non-apple accessory that worked intermittently, often with a message 'device not supported'. Another I bought as a 'shopping basket extra' because it was only 99p turned out to be over-priced at that since it didn't work at all despite looking perfectly normal.
I would suggest getting a new expensive Apple cable since that obviously seemed to fix it. Don't be tempted to buy a cheaper one though.
Alan