English Translation
You may be able to read the handwriting on the wall, which is an omen for disaster, but it is Greek to me.
The audio is incorrect and the transcript is correct. 禍 is pronounced as わざわい.
禍の前兆である壁上の書きもの is an awkward translation. I would propose to rephrase:
あなたには壁に記された手書きの内容が禍の前兆に読めるかもしれないが、私にはチンプンカンプンだ。（あなたにはかべにしるされたてがきのないようが…）
Handwriting = 手書きする (gerund) or 手書きの内容 (result of handwriting)
壁に記された: 記す means “to keep the facts”. 日記, for example, is “a diary”. The objects of 記す can be letters/characters or drawing. The action of 記す can be done in paper, stones, walls, animal skins, or even in someone’s memory.
書きもの is awkward for wall. 書き物（かきもの） or 書物（しょもつ）is usually in the form of book or a bunch of papers.
チンプンカンプン is more frequently spelled in 片仮名.