Ah you're right Giant. We forgot to mention that ComSpec has to be added to ioftpd.env in ioFTPD/etc dir in order to get it to work as wanted.
Check your enviroment variables in windows to see which ComSpec-path is used in your computer.
Example for win2k:
ComSpec=C:\WINNT\system32\cmd.exe
WinXP should be ComSpec=C:\WINDOWS\system32\cmd.exe or something like that.
It should work now
WarC has added the additional info to manual.