[yocto] error: runqemu command not fonund, when "$ runqemu qemux86 bzImage-qemux86.bin core-image-lsb-qt3-qemux86.ext3" THx!

[jack]

hi,all! I Use a pre-built image and run it in the QEMU emulator.
I have downloaded and installed 
"poky-eglibc-i686-i586-toolchain-gmae-1.1.1.tar.bz2", then I downloaded 
"bzImage-qemux86.bin"  and  "core-image-lsb-qt3-qemux86.ext3"
but when
"$ runqemu qemux86 bzImage-qemux86.bin core-image-lsb-qt3-qemux86.ext3"
error like below:
error: runqemu command not fonund