Using the AT command

Why won’t my scheduled task run? I use the AT command to schedule server reboots, that works great now. However, I’ve been playing with this feature to automate other tasks. I attempted to use AT to open notepad.exe though, as a test, and it simply will not work. I use the sytax:

AT \\servername 12:00 /every:s c:\winnt\notepad.exe

The time comes and goes with no notepad. Any ideas? Are there limitations to what executables can be opened?

Thanks,
Kurt G.