I'll try without glx right now...
And that was the clue !
But even if X started with nvidia drivers... I've fixed nothing at all ! glx just doesn't work.
Is there a link with the fact i use debian which usually works with the nvidia-glx package (which can't be installed when installing nvidia drivers manually...) ?
And also, the bug with amarok appeared again... since it only runs when nvidia-glx is installed, don't know why...
[EDIT] Attached the nvidia-bug-report.log