1. Error source

German native speakers like to use the Present Simple because in German the present continuous tense does not exist. However, if you talk about things that are happening right now, you must use the Present Continous in English!

Example:
Wrong: At the moment I work on my PHP application.
Right: At the moment I am working on my PHP application.

Both sentences in German:
Momentan arbeite ich an meiner PHP Applikation.