About quartus11.0sp1 generate lpm mult error

I use win7 + quartus 11.0sp1. When I generate a lpm mult module, there is a error window pop up after I push the fiinish button.

Error: mega_lpm_multq.exe has been stoped working.

Close the program.

I guess the problem is win7 and quartus are not compatible.

Did anyone encountered that case?

How can I solve it?