ModelSim- Create Wave: Error in Tcl script

I use ModelSim Altera Starter Edition 10.0c to do my VHDL Simulation.

When I try to create input signal(right click on vhdl file name under work library, and then click Create Wave), I got the error message below.

Error in Tcl Script

Error: command"duInfo" already exists in namespace"::"

Thanks for any help