I keep getting a W3001 : Error while executing plugin:

I keep getting a W3001 : Error while executing plugin: Error converting file: VMerror

Create PDF: W1603 : Plugin failed

How do I fix this error? The Create output works, and Post Script it creates works through Adobe Distiller. But the Create PDF Pass through gives this error only on some jobs.

I cannot determine when this happens. Anyone else experience this?

Figured it out. Two reasons, bad PDF as a background image, and the output preset was not set to define by workflow.