leds do not light when holding boot button


I want to install a new linux to my beagle.

I created a boot disk on a micro-sd card by writing RuneAudio_bbb_0.2-beta.img to it.
I then insert the card and hold the boot button and power up.
I hold the button for a very long time (at least 20 seconds ), but I do not see one on of the leds lighting up.
Only the power led is on.

I I start the beagle without holding the boot button, the 4 leds start flickering after 4 seconds.

Can anybody help tell me what might be wrong?