Could you please tell me why the following phrases are incorrect?

1)After years of PREPARING and weeks of rehearsals the production has to be ready for the public and the critics.
2)The critics are the most FRIGHTENING people on the first night because their opinions will either help make the show a hit or force it to close.

Thanks.

1. Instead of pr participle there should be the noun 'preparation'
2. There's a quite obvious mistake: 'frightening' (as a noun or a pr participle) cannot be used with 'the most' that stands for superlative degree of adjectives; actually 'frightful' is correct.