He's running NET START 3 times for the same reason that you are posting this question & why I'm replying. Sometimes, SEP just does not seem to start & you have to retry multiple times until the yellow shield appears in the system Tray.
As to why your script does not want to run, remember that SMC.EXE is not in your PATH, thus your DOS prompt for the script doesn't know where to start SMC.EXE from. It works from the Start -> Run... box because it is registered as a known ammplication in this Registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\Smc.exe
If you've upgraded from SAV 10, this will point to C:\Program Files\Symantec Antivirus, for a new install, this will point to C:\Program Files\Symantec\Symantec Endpoint Protection.
Have you looked at using SC.EXE instead of NET.EXE START? SC.EXE is a replacement for NET.EXE & has more smarts. You can configure Services & verify the status with SC.EXE query [ServiceName]. You'll see a state of STARTING or RUNNING or STOPPED. You could use that in your script to ensure the SEP services are running again.