Why does the PCI Express example design fail to simulate in the Synopsys VCS simultion tool?

Due to a problem in the Quartus ® II Software version 12.1, errors may be seen when simulating the PCI Express Qsys example design using the autogenerated simulation scripts for the Synopsys VCS_MX tools.

One of the following errors may be seen:

Error-[MPD] Module previously declared
  The module was previously declared at: 
"./../..//pcie_de_gen1_x4_ast64_tb/simulation/submodules/altpcietb_bfm_rp_gen2_x8.v",
  47
  It is redeclared later at:
 "./../..//pcie_de_gen1_x4_ast64_tb/simulation/submodules/altpcietb_bfm_rp_gen2_x8.v",

Error-[URMI] Unresolved modules
 ./../..//pcie_de_gen1_x4_ast64_tb/simulation/submodules/altpcietb_bfm_top_rp.v, 454
  "altpcietb_bfm_log_common bfm_log_common( .dummy_out (bfm_log_common_dummy_out));"
  Module definition of above instance is not found in the design.

To workaround this problem in the Quartus II Software version 12.1 follow the steps below:

1. Open the generated simulation script <path>/testbench/simulaiton/vcsmx/vcsmx_setup.sh in a text editor
   Update USER_DEFINED_ELAB_OPTIONS to add in the required library include path:
     USER_DEFINED_ELAB_OPTIONS="-y ../../<design name>_tb/simulation/submodules/"
2. Open the following file in a text editor:  <path>/testbench/<design name>_tb/simulation/submodules/altpcietb_bfm_rp_gen2_x8.v
3. Locate the dupicate module definition by searching for module altpcietb_bfm_log_common and comment out the second instance (Lines 888-1247)
4. Re-run the simulation script  ./vcsmx_setup.sh

This problem is scheduled to be fixed in a future version of the Quartus II software