Never seen this before!
Just imported some job binary for normally well behaved jobs on a new DS6.9 SP6 server (on Windows 2008 R2 with SQL Server 2012) and started getting this error on tasks running embedded scripts.
Never seen this before which is odd as I've been using these job sets for years (since SP4). It's an access denied problem... and sometimes it happens... sometimes it doesn't.
Feels like a support ticket is looming... :-(