Hey,
I played with enders client normaly for many days. Then one day when I tried to login I got some glitchy black screen and couldn't move(note that this doesn't happen with the normal client, only enders). I tried reinstalling, searched the forums and nothing, and then out of nowhere, after I reboot my laptop and did so many other things i dont even remember, it started working again.
Yesterday I got the same thing again. And as usual, I tried reinstall, reboot e nothing.
So, I saw that some people in the Enders topic had similar problems...
Here's what made my Enders's client back to normal...
I just changed the color's from 16bits to 32bits... It worked like magic! (And yes, i had changed the colors to 16bits yesterday to run another game, so it makes sense)
Hope it helped someone... I tried search the forum for some information about this and found nothing.