Unable to simulate more than one module per project

I am unable to simulate more than one module in one project. I created a Quartus project and added a Megawizard core, wrote a testbench for the core and simulated it. I am adding another core and wrote a testbench for it. However when I try to run the Modelsim simulation through Nativelink I get the error in Modelsim:

Module 'divunitfunc' is not defined.

divunitfunc is the name I gave to the core when created through Megawizard.

I defined all the settings for this simulation in the Nativelink simulation settings dialog box appropriately.

Also, in the Nativelinks settings for testbenches, for the testbench not running properly, I have defined the toplevel module as the name of the module I used in the testbench file.

Can anyone help?