Error: 'C:/build/swbuild/SJ/nightly/18.1std/625/l64/work/modelsim/eda/sim_lib/altera_mf.v' doesn't exist.

Thanks for reverting. The problem is solved now. I don't remember the exact solution. Probably when we re-installed the Altera libraries, things were fine. And the other thing i remember is, my simulation was getting stuck due to the TB code. Not sure, why the above messages were displayed when i broke the simulation. With above two fixes, things look good.