Help !!! my iphone

Today I didnt do anything to my iphone 2G.

But suddenly a msg pop up as below :
This accessory is not made to work with iphone.
Would u like to turn on Airplane mode to reduce audio interference ?
You will not be able to make or rec'd calls.
YES or No.

This msg pop up many times.
No matter Yes or No i press. it look like not working at all.
Then I found that my iphone no sounds come out for ringtones, sms tone, keyboard clip and even ipod.

I tried to re-set my iphone, but the situation still same...

Pls tell me what wrong of my iphone ? How to solve it.

Pls help !..

TQ