P20 - Attempt to look up a non-existent column in the table

Most problems are detected when Inform translates the source text, but this is one of the exceptions, a "run-time problem" which emerges only during play.

Suppose there are two tables, the Table of Fruits and the Table of Fowls, and suppose that the former has a column called seeds. Inform will (mostly) translate a request to talk about the seeds entry in a row of the Table of Fowls, but such a request can't make sense: the other table has the seeds column but this one doesn't. This problem will be detected at run-time, and this is the message which then appears.