Early 6.8A versions of Adagio would report this error if a "hint" popped up and the user pressed the Enter key while the hint was displayed.

Certainly it is fixed in the current release of Payables (V6.8B 040506).

Also, if Payables exited abnormally, then a record may be marked in use that isn't actually. Adagio resets all of these statuses if it can when a module is launched (which would explain why the problem "went away").