@reyalp: that was it.... must be too late yesterday, in my USB remote script I used 'sleep' but for some strange reason I switched it to 'delay' in this script

with 'sleep' it works as expected. I'd like to use 'shoot' because as I understand it, the command will wait until the camera has finished taking the picture, while pressing and releasing the shutter will not, is that right? For taking hires panoramas every second counts, so I want to switch on a LED while shooting, and when the cam is ready to take the next picture, I'd switch the LED off, so my PanoHead knows that it can move to the next position. Working with delays ist not really an option, because I would have to change that depending on the type of panorama I'm shooting (HDR, night shots, sunny shots...). The wiki I have already found, it was my starting point. One thing I dont understand is, that I got the error in line 4 and not 3.....
Thanks alot!
Volker