Anyone who knows how to solve this problem?
For Mac
install.packages("/users/frederikpieters/Desktop/EconometricsUGent_1.0.tar.gz", type="source", repos = NULL)
Warning: invalid package ‘/users/frederikpieters/Desktop/EconometricsUGent_1.0.tar.gz’
Error: ERROR: no packages specified
Warning in install.packages :
installation of package ‘/users/frederikpieters/Desktop/EconometricsUGent_1.0.tar.gz’ had non-zero exit status