That's not the proper way to install it. You need to leave the file as a zip, and it needs to be on the root level of the SD card. Then boot into the recovery mode, by first turning off the phone. Then hold down the home button while holding the red "power" button at the same time, unitl you see the black screen with the green writing. Then select backup/restore. Make a nandroid backup. After that is finished, select wipe, and wipe both data and dalvik...then select flash zip from sd. Next, reboot and enjoy your new rom!
All this is based on the fact that you are rooted. If not, go
HERE and re-read the procedure to root your phone. Let us know how it goes.