Hi @angelczl -
That message means that the spatial layers must have a projected coordinate system assigned, with linear units like meters. It is likely that the inputs that you provided have a geographic coordinate system (like WGS84), where the units are in degrees.
The model requires that all spatial inputs be in exactly the same projected coordinate system, with linear units in meters. Please see the User Guide for a further description of the requirements. Try doing a Reproject (ArcGIS) or Warp (QGIS) on your layers to give them the same projected coordinate system, try running the model again and let us know how it goes.
~ Stacie