I’ve encountered this error message on various Sitecore implementations predominantly while publishing. It’s painful as its fatal to publishing process and Content Editors get uppity when they see the stack trace in the Publishing window.
Control Users Publishing Options via Sitecore Security Policies
As with most go-lives a showstopper ticket comes in just as you feel like you can finally go live. Fortunately the issue came in didn’t require a new release only some digging around in Sitecore and learning about a lesser known feature