Questions & Answers about Me frustra que él no escriba el informe.
Why is it escriba instead of escribe?
Escriba is the present subjunctive form of escribir. We use it here because the first part of the sentence expresses an emotion (Me frustra) and there is a change of subject. You are reacting to an action that someone else (él) is doing.
Why do we say Me frustra instead of Yo frustro?
Is the word él strictly necessary in this sentence?
It is highly recommended here for clarity. In the present subjunctive, the conjugations for I, he, she, and you formal are identical (they are all escriba). Without él, the sentence could mistakenly be understood as 'It frustrates me that I don't write the report.'