I know this is old but maybe this helps. I would Imagine (I am supposing here) that your data pins are soldered to close together and somehow interfere or that one of your data is soldered to close to the voltage or ground: Nokia chargers shortcut the data+ and data- pins so it knows it is a charger. Maybe if it does not show i with your computer its because those pins are shorting themselves. Something similar could be happening when plugging into the charger, it might be shorting with one of the data ports and hence disconnects. I want to believe that your data- is touching/shorting the ground (or voltage- in some places) and hence it messes up. Give it a look and come back with anything
That is because if you don't need to solder the pins you need only to reinforce the connector. And that is not too difficult to do. But you must do that soon if your connector get out of place. If not you will need to solder the pins too. And that is the hard/dangerous part.