This error occur if List Fields can't decide which document to work with. Most likely has List Fields been started without using the Action-menu in Lotus Notes.
Unfortunately List Fields can't continue, and will terminate.
See Also
Messages
E000: Lotus Notes client is not running!
E001: The Lotus Domino Designer is on top
E002: The Domino Administrator is on top
E003: Is List Fields installed correctly ?
E005: The Notes database can't be opened
E006: The Notes document hasn't been saved yet!
E007: The document couldn't be read!
E008: Notes.ini could not be found in any PATH directories
W001: Have you saved the Notes document ?
W002: The size of all attachments combined is too large for high quality rendering
W003: The size of one of the attachments is too large for quality rendering
W004: Can't save or open attachments right now!
I003: List Fields Debug Session database is about to be created
I004: List Fields Debug Session database created
Q001: Do you want to save your changes ?
Q002: Do you want to delete the currently selected field ?
