Can anyone tell me if they see errors?

[steady eagle]

Yes, I do see errors.

[plain sparrow]

1.1: the verb construction is 'mit etwas einverstanden sein'

1.12: not wrong per se, but the task appears to be prepositions and wo-composita. Warum is just a normal question word. When 'ich freue mich über etwas' I am happy about it

18: mit etwas aufhören

[raven jungle]

Sorry I'm not sure I quite understand what you mean

[plain sparrow]

did you look at what you wrote?

[raven jungle]

Uh yeah

[plain sparrow]

You wrote 'worüber bist du nicht einverstanden'

I am not 'über etwas einverstanden sein' rather 'mit etwas einverstanden sein'

The third task is pretty much all wrong

[raven jungle]

Are you saying it ain't über?

[plain sparrow]

yes

I have to go, but for task 3:
If the questions is about an object, you need to use wo- + preposition to build the question word, just like the questions you answered in task 2. If the question is about a person then you would use preposition + wer/wen/wem

i.e.
Worüber freust du dich? (what are you happy about)
Auf wen freust du dich? (who are you looking forward to)