"This accessory is not compatible with iPhone" message

[margaret.179]

Currently my iPhone 3GS constantly displays this message when there is nothing connected to it. However, it's also playing up as it won't play music outloud or any apps' sounds. BUT it will play perfectly well when there are headphones in the headphone jack.

I've been told to try to clean out the headphone jack with tissue, but this has not worked. Every now and then the phone will play music outloud, but more often than not.

 

[cwa107]

I would lean more toward a bent pin in the dock connector. Take a close look at it and see if all the pins are straight.