ModelSim keeps trying to pull a primitives library file from a nonexistent directory in my project folder. How do I tell it to use the sim-lib?

When trying to run a test bench file, I get the following error:

# ** Error: (vlog-7) Failed to open design unit file "C:/PROJECT_DIRECTORY/../../../../altera/13.0sp1/quartus/eda/sim_lib/altera_primitives.v" in read mode.
# 
# No such file or directory. (errno = ENOENT)
# ** Error: C:/altera/13.0sp1/modelsim_ase/win32aloem/vlog failed.

This is caused by one of my top level entity code blocks using the "soft" function from a library file. But why is it trying to look for this file in an unknown and nonexistent folder within my project when I've called out the library locations within ModelSim and within Quartus? And is there a way to find out what those "/../../../../" folders are? I looked in the log file and it still has those.