Simulating MegaWizard ALT_MULT on Modelsim

Hello i am trying to simulating MegaWizard ALT_MULT on Modelsim but i am having the problem

** Error: (vsim-3033) C:/Reason/Projetos/multiprocessor_tutorial_start_v1/mult.v(701): Instantiation of 'lpm_mult' failed. The design unit was not found.#          Region: /tb_proj/dut/mult_inst/mult_altfp_mult_9tn_component#          Searched libraries:#              C:\altera\11.0\modelsim_ase\altera\verilog\altera_mf#              C:\Reason\Projetos\multiprocessor_tutorial_start_v1\testbench\work

Should the library be at

C:\altera\11.0\modelsim_ase\altera\verilog\altera_mf

?

I am trying to add the library in the GUI but it seems not to work..