<p>I have a new German RepRap NEO 3D printer, and when I try heating the Extruder to 215°C with Repetier-Host Mac 1.0.1, it always stops at 130°C - does anybody have an idea what could be the reason?</p>

A few possiblitites.
You wire is too small. If your wire is HOT that is a fire hazard.
Your thermistor is bad. Check with a high temp heat probe or try replacing thermistor.
Your heating element is bad (rare).
Last it could be a limit in your firmware. But that would surprise me.
Any chance you have the bed and the hotend reversed? If you had the Bed as Hotend, then it would max out around 100. This last one I would say is most likely..