Z3 answering machine bug- black screen? topic

I just got the Z3... and trying out the answering machine... very confused.

For some reason, when I play back the message left on the answering machine, the screen goes completely black? The home button doesn't work (I hit it, but the screen still remains black)? Any clue what's happening?

Also, when I put the phone on speaker to play the message, the volume is still very quiet

EDIT OK- screen no longer turning black... I have NO clue what was happening

Thanks