So I've been trying to make a master cost raster (taking into account the slope and landcover data). However I can't make the r.mapcalculator work... I tried with r.mapcalc but the interface looks so different from the tutorial I'm using (http://gracilis.carleton.ca/CUOSGwiki/index.php/Evaluating_Landscape_Permeability_in_Quantum) and I ended up not being able to perform the analysis.
I also can't use any of the functions from the "GRASS commands" tab (even though the tab GRASS GIS 7 works fine. I tried installing QGIS over again, taking a look at the directory GRASS is installed and nothing seems to work.