Question about intalling EDK9.1i

Hello, I intalled the ISE9.1i and updated it. It can work. Then I installed EDK9.1i. But when I run it, it told me "The procedure entry point ptw32_push_cleanup" could not be located in the dynamic link library libpthread.dll." I intalled them on a Windows XP machine. I have no clue about this error. Can anybody give me some suggestion? Thanks a lot, Rebecca