rotation stopping...

I have some rotating lights that I remotely control with a hud. The rotation is in the root prim, making the whole thing rotate. With the hud, I control the light-beam, changing colors and switching them on and off by using llRegionSay...
Strangely, the rotation - which has no other script nor listener in it - stops after a while...
(I use llTargetOmega(<0,0,.25> * llGetLocalRot(),PI,1.0); for the rotation).
I built a reset in it now, to make them start spinning again, but this is kind of annoying since I have to do it quite often...

A strange thing is, that when the rotation stops and I use the edit function just to select and deselect the lights, the rotation starts again...

Any ideas?

I'd love to know the answer to this one, too. I've had something like this happen on an application of llTargetRot where the script stopped and restarted the rotation, with the restart sometimes failing--but in that case, a reset would not get it to start again, only a recompile would. I've been meaning to try something like a bogus llSetText that would force a prim update whenever restarting rotation, but dunno if that would have any effect or not. (It's hard to test cuz it can take weeks before it fails.)