My iPhone isn't connecting to itunes

[iMore Question]

My parents have an existing iTunes account with all of our music on it. I have a different Apple ID than they have for their iTunes account. Every time I plug my phone into the computer, the computer says "itunes could not connect to the iPhone because an invalid response was received from the device". And my phone also says "do you trust this computer?". And of course I answer; trust. But nothing changes, help would be greatly appreciated.