Hello,
I had a similar problem today.
I have done the following:
http://www.symantec.com/business/support/index?page=content&id=TECH211634
Then, the variable % DEPLOYMENTDIR% under Settings -> Deployment and Migration -> Packages was away, and I have change the location under Package entered the direct path.
Then I have a repair the DeploymentSolution and then the DeploymentSolution HF6.
Then I updated the distribution points and recreated the Preboot Enviroment.
greeting
Robert