Wake on Lan stops working when right clicking on a machine and choosing Power Control and then Wake-Up. This also applies to assigning jobs to machines that are powered off. The initial WOL packet that gets sent to start the job may not get sent so the machine won't wake up to perform the work.
There is no error message present for this issue.
The issue is currently being reported in GSS 3.1 MP5 but it may apply to previous versions back to GSS 3.1.
Currently there isn't a root cause for this issue.
There is currently not a permanent resolution for this issue. Development is aware of the issue and is currently working towards a fix. Please subscribe to this tech article and you will be notified when a fix is available.
As a work around, you can simply restart the Altiris eXpress Server service and the issue with go away for a while.
If the workaround dose not resolve the issue please see the troubleshooting Wake On LAN article at: http://www.symantec.com/docs/TECH239922