I also have been a happy SlickRun user since I tried it, but a couple of days ago I realised that Sycon's IDEA! --an information manager that I regularly use for my work- didn't operate as it was supposed to. Through their support I cornered the fault to the SlickRun Magic Word I use to launch IDEA!
Indeed, all worked well if I launched the program through its normal shortcut; interestingly, the parameters (target, path) were exactly the same, i.e. copy/pasted from the shortcut to the MagicWord.
Your post prompted me to give it another try; I now know what the exact issue is: SlickRun apparently doesn't need --actually it dislikes- quotes around paths --something that Windows shortcuts require for paths including spaces.
I removed the quotes and all is well.
P.S. Incidentally, Sycon's support was provided via phone and PC Visit ( http://www.pcvisit.de/index.php?id=72&L=1
), an absolutely brilliantly effective way to show your PC screen to a technician. The whole session was finished in less than ten minutes, during which they found what the trouble was on two separate issues, uploaded me a patch and tested its success.