use a .exe that takes an argument to launch another file. I had this problem in the past when trying to launch a ppt. There's programs out there. let me see if i can find one.
Another alternative:
put start before the file you want to run. this will launch a command prompt for a moment before launching the file
code:
[autorun]
open=start file.txt
Here, this program should do the trick:
http://www.naughter.com/shelexec.html