iPhone moisture in connector socket

There seems to be an issue with the iPhone, when the cable is plugged in, the charger never charges the phone. It always stays on the red charge indicator.
The shop from where it was purchased says that its moisture in the connector port. They will want to charge €200.
Is there anyway to solve this issue with some easy steps/checks first?
Thanks in advance
G5 Dual 1.8(10.5.8) + G4 400 AGP(10.2)+ MacBook 2GHz Core 2 Duo(10.6.2) Mac OS X (10.6.6) 1.5Gbs RAM iPhone 3G iPod 5G 30gbs Black Magic Mouse