Synopsis VCS fails with an error Error- [MPD] Module previously declared

If you use the MegaWizard Plug-In Manager to create two or more IP variations in your design, simulation of the design with Synopsys VCS / VCS MX fails with an error similar to the following:

Error-[MPD] Module previously declared

The file set for simulating your entire design contains duplicate files. This duplication may occur if your design has multiple variations of the same IP core, or if different IP cores share some simulation files (for example, SystemVerilog packages common to multiple IP cores).For some IP cores, during IP file generation of an IP variation, a complete simulation file set is added to the <variation>_sim directory. Each variation's file set includes copies of all the IP simulation model files required to simulate the variation, including some files that may be shared with other IP cores.The concatenated list of all simulation files names for all IP variations (including the duplicate filenames) that is added to the VCS command line causes the error.NOTE: The file set does not include copies of the simulation library files that are installed in the quartus/eda/sim_lib directory and directories below it.

Refer to the solution available http://www.altera.com/support/kdb/solutions/rd05172011_198.html