Help with Tamamo 's freeform door script

can someone explain how to set up the door sprites for this script?

I downloaded the example quest and I couldn't figure it out.

It doesn't work for me anyway:

Code:

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[INFO] External ZScript Parser

[Info] Compiling the editor script buffer...
[Info] Pass 1: Parsing
[Info] Pass 2: Preprocessing
[Info] Pass 3: Registration
[Info] Pass 4: Analyzing Code
[Error] ZQ_BUFFER Line 56 @ Columns 9-25 - Error T021: Function OppositeDir(int) has not been declared.
[Info] Failure!

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