The user has permissions to run a report in the console but cannot do so from the ReportManagementService web service. The web service returns the message:
"The user does not have permissions to run this report."
ITMS 7.6, 8.0, 8.1
This will be resolved in the coming 8.1 RU6 release and later versions.
If you are in urgent need of a workaround in advance of this, please contact Symantec support, quoting this article ID