I have the same issue.  Please share if you are able to solve this problem.  
Thanks!

did you a) update the launcher and b) actually download and install boxee using 
the launcher?

I have the same exact problem. Using 1.0.b10 with aTV 2.3.1 using mac os 10.5.7.
Everything goes well. I get it installed. I update to the latest boxee build. 
select
boxee and goes blank. If I move arrows up or down I can hear boxee doing the
selections but it just displays black screen. 

thanks for your help

andresh82,

did you update the launcher?

I have the same issue as well.  I updated the launcher and then downloaded 
boxee. 
Same result - quick flash of the apple and then a blank screen.

I have the same problem too - HELP!

I am having the same problem as well

What Launche version do you have? (Launcher -> About)

ya im having the same problem but it is not when i download boxee it is when i 
got to load other 3th party software it will download they stuff but when i 
exit the downloaded screen it says press play/stop botten to restart and it 
will play music and i can hear the sound effects but nothing but a blank 
screen. Oh and the screen saver will play. what do i do???

It's not the same problem then if it is not when you use Boxee. I would say you 
should've created a new issue, but that's actually not necessary because:
1. You have installed atv-files, you should have searched for this issue. All 
you need to do is rm -rf the folder from Finder.app's plugins folder. 
2. It's third party software as you said; we don't support it.