Scripting Limitations/unable to run certain commands in C:\WINDOWS\System32

I have the following script that I am deploying to a LogMeIn session with private session mode (using link to download LogMeIn agent and not calling card). The LogMeIn technician console and the agent are on the same machine. I am running both as the same AD user:

@echo off
C:\WINDOWS\System32\cmd.exe /c echo cmd test
C:\WINDOWS\System32\msg.exe "%username%" /time:0 Hello World

When I try deploying it via LogMeIn I will see the output of the 2nd line "cmd test" but for line 3 I get the following I get 'C:\WINDOWS\System32\msg.exe' is not recognized as an internal or external command, operable program or batch file.

Why am I able to run C:\WINDOWS\System32\cmd.exe but not C:\WINDOWS\System32\msg.exe?

• I am able to run the 3rd line if I manually run it directly on command line outside of LogMeIn agent.
• I still have this issue if I give UAC permission to the LogMeIn agent.
• When I deploy a script that runs whoami I get the same output as running the command directly on cmd outside of LogMeIn.
• If I deploy msg instead of the full path I get 'msg' is not recognized as an internal or external command,
  operable program or batch file. I don't get this when I run it directly on the command line outside of LogMeIn.

I'm stumped why this is happening and wonder if this means scripting is more limited than meets the eye.