strange button behavior, makes screenhots almost every time

Hi,

I own a 3rd gen iPod Touch (32GB)

I can power it on normally, but I neither cannot power it of or go back to the application Screen because every time it takes a screenshot.

To be direct:

Press power button -> Screenshot, iPod does not turn off

Press home button -> Screenshot, iPod does not got back to app overview

Sometime the volume buttons will also take a screenshot

There are also error events in the log