What is the ruling on taking sums of money from companies in exchange for training courses, for which external lecturers are arranged, and the costs of the training hall are paid from these sums?

There is no objection to overseeing the establishment of educational and training courses and receiving payment in advance. This type of hiring is called "hiring of a described entity in trust" (ijārat 'ayn mawṣūfah fī al-dhimmah), and it is not a condition that a specific person perform the work. Scholars have agreed on the permissibility of paying the entire wage in advance; indeed, some even made it obligatory as a condition for the permissibility of the hiring agreement.