Some output functions can't handle spaces in pathnames

[jrfaeder]

The attached file generates an error from writeMfile if the path to the output file contains a space in the path. The simulation is carried out, but the model is not written to file prior to the simulation as specified by actions. Both writeMfile and writeMexfile use the same code to open the output file and so both need to be addressed. Both make the function call File::Spec->splitpath($prefix), which is likely where the problem arises.
test.bngl.txt