For what I've read this has been a common problem with delta printers in previous versions of repetier host.
I am having this problem in manual control, even without making any movement. I just plug everything and it seems to be right. I can home it, I can perform some test movements and then, at some point, it will hang.
If I don't do anything else than homing it it will hang in a couple of minutes or so. When I try to make any movement it will be queued.
I have reinstalled the host (v 1.0.6) and reloaded the firmware into the arduino board.
Any ideas?