You need to create an empty /strings folder in your Thief folder, then all will be well.

If you want to display a short text on the screen, and tnhscript is already loaded, TrapText
(http://dromed.whoopdedo.org/tnhscript/traptext)
can display it without a book folder. Just type your text in the Design Note (Add--Editor--Design Note)

StdDoor<dd>gen.osm 1/G/2The door is opened by the messages <code>TurnOn</code> or <code>Open</code>. It is closed with <code>TurnOff</code> or <code>Close</code>. It is also operates in response to <code>FrobWorldEnd</code>. Frobbing normally toggles the state of the door. In Thief 2, if the door had previously been halted, frobbing it will reverse the action it was engaged in before the halt. The door states are closed, open, closing, opening, and halted. A door that is locked and closed cannot be opened by <code>FrobWorldEnd</code>. Instead, it plays an environmental schema with the event tags <code>Event Reject, Operation OpenDoor</code>. The lock is disregarded when the door opens any other way. The lock will also be disregarded if the config variable <code>LockCheat</code> is set (only in Thief 2). When a door is locked, it will close itself. Unlocking a door also opens it. Doors cannot be killed. When <code>Slain</code>, the door will be resurrected with 1 hit point. Any <code>Lock</code> links from the door are removed, and the <code>Engine Features\Locked</code> and <code>Engine Features\KeyDst</code> properties are removed. The <code>Engine Features\Locked</code> property is set to 0 before being removed, so the door will receive a <code>NowUnlocked</code> message. The door opens with it is slain. In Thief 2, if the door has the <code>Script\Timing</code> property, it will automatically close itself that many milliseconds after it is opened. The timer aborts if the door begins to close. When the door state changes, an environmental schema is played with the event tags <code>Event StateChange, OpenState <state></state>, OldOpenState ><state></state></code>. Previous schemas are halted if the state is closed or open. If the door had recently been frobbed by the player, with <code>FrobWorldEnd</code> or <code>PlayerToolFrob</code>, the tag <code>CreatureType Player</code> is added to the list. The flag that determines whether to add the tag is cleared when the door state is closed, open, or halted. When the door is opened, it will set a secret as being found if it is marked as <code>Hidden</code> in <code>Dark Gamesys\Stats</code>. Two or more doors can be combined into a set of "double" doors by creating <code>ScriptParams</code> links between the doors and setting the link data to <code>Double</code>. There must be at least one link between any two doors in a group. More than one link between two doors is unnecessary, but harmless. The doors will keep in synch for most state changes. A halted door will not cause the linked doors to halt. If the linked doors are meant to be locked, they should all have the <code>Engine Features\Locked</code> property (or a <code>Lock</code> link). A door without the property will not synch properly with the others. (This is because it might have been <code>Slain</code> and lost the property that way.) Doors keep in synch by sending the <code>SynchUp</code> message from the door that had its state changed to each door it has a link with. When a double door spans an opening, it can cause AI to get stuck between them. The AI tries to frob both doors, which makes them start to open, then immediately close. Thief 2 solves this by creating a marker with the property <code>AI\Utility\Path avoid</code> on it. The marker is placed at the midpoint between two doors, but only if the doors share a room boundary, and are touching (or close to) at the midpoint. The marker will be created for pairs of doors with a <code>ScriptParams</code> link between them, regardless of whether the data is set to <code>Double</code>. So you can take advantage of the feature without having to synchronize the doors.
</dd>Keep in mind that link data is case-sensitive. It's "Double" not "double". And why is it that these descriptions keep getting longer and longer the more of them I do?