Have you tested the script by selecting run script?
If it does not run then check email settings.
If it runs and sends email then follow the logic below:
What are the script policies assigned?
Do you have other than read, write, test and reboot?
If yes deactivate all besides the above and test the script from netwatch.
Please refer to
http://forum.mikrotik.com/t/netwatch-deprecated/119579/1