Run-time problem

P41 - Attempt to match a snippet value which is currently invalid

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.

A snippet is a fragment of the player's current command, but it does not record the actual text: instead, it notes only the word numbers. (Thus in TAKE ME TO THE RIVER, a snippet would be words 2 to 4 rather than the text ME TO THE.) Snippets go out of date as soon as a new command has come along, so shouldn't be kept in longer-term storage. At any rate, the one you've just tried to match against goes outside the range of the current command, so it can't be right.