I tried that too. This time i kept the executable on the remote machine, but it still gave the error 8.
Code:
  
$computer = "itl-hw-22254d" ;Remote machine
$rc = fnRemoteExec('c:\WINNT\yahoo.exe', $computer)

? $rc


One more thing, i m running the script from XP machine, while the remote machine has 2K Pro installed on it.