Problem charging European with battery backup charger

[mark mithe]

I bought a Switchway 1900 mha battery charger and used it for several months to recharge my iPhone 3g purchased in the US. I gave the charger to a friend in italy. She says it will not charge her iPhone 3g purchased in italy. She plugs it in but the battery icon in the upper corner doesn't indicate that it is being charged.
Is there any physical difference in iPhones made for the US vs. those made for Europe that would prevent the charger from working on her phone?
Mark

 

[Hawk]

The only difference I know of is the voltage at the plug, but that shouldn't affect anything on the phone.
I think she might need to get some canned air and blow out and clean both her charge port and the connector from the battery to make sure that it's making a proper connection.
I bought my boss a new cheap data cable, and at first it wasn't working for him, but his stock one did. After inspecting his phone and the new cable, I found that he had a years worth of pocket lint built up in the phone's port. I cleaned it out and everything worked fine. The new cable's pins were slightly more recessed than the stock one, so that is why there was a problem.