"I am not walking any more today."
Translation:Ma már nem sétálok.
Maybe because of the accentuation. "Sétálok" should be used instead of "sétalók". Sétalók is not a proper word in Hungarian. The other possible explanation is that "Nem sétálok ma már" sounds a little bit unnatural. Different word order conveys different message in HU. By default, the verb carries the core message; any information that is more important will precede the verb. The most important information here is "ma már".
Your sentence means that "I am not walking any further today." However, you can say "Ma nem sétálok többet."