Itouch usb connection interference for 207 Envy

[CPFC84]

Hello all - I hope some one out there can help!

I have an Itouch with a lead I plug in to the USB connect hub in my 207 Envy model. The songs play ok, however after 30 seconds or so there is a pause. This problem may or may not repeat itself every 30 seconds or so throughout the remainder of the track. It all seems very random, and I have tested my sister's Itouch and both are equally bad. I have also tested alternative leads to no avail.

I just don't understand how there can be any interference? Any help would be appreciated as I got an Itouch so I can play music in my car with higher quality, and mostly it is - just need to iron out this minor annoyance