All of a sudden I don't get an error when entering an unvalid command.

This is how it looks....

> kljfdkfjdslk

> sdklf sdjlkfdjf

> kldsfjdslkfjds

> look
(the room description is shown)

as opposed to...

>  kljfdkfjdslk
I don't understand your command.

> sdklf sdjlkfdjf
I don't understand your command.

> kldsfjdslkfjds
I don't understand your command.

> look
(the room description is shown)

I've checked the templates and everything seems to be in order.
It just... happened.

Any ideas why?
And... how to fix it?

No idea why that would have happened. Could you link the game?

I'll PM the link. It's way too early to let people play it :)
Thanks for looking.

Hmm... this was empty in full code view for some reason

    <unresolvedcommandhandler type="script">
    </unresolvedcommandhandler>

I changed it to

    <unresolvedcommandhandler type="script">
      msg ("{random:I'm not sure what you're trying to do?:Huh?:Wait... what?:Try something else.:Well that won't work.:I don't understand that command.}")
    </unresolvedcommandhandler>

... and it's working again. I'm rarely in F9 mode so I have no idea how it happened in the first place.
Either way, it's solved. You don't have to take time to long into it Mr Angel.

It's greatly appreciated though!