I had that happen to me a couple time on the same zip file. I re-down loaded it and ran it again. I worked just find. So, it may be a corrupted zip file. Try downloading it from another source, also.
HTC EVO 4G - rooted - Gingerbread
PS Also you should name it update.zip, I've seen people suggest this many times.
Last edited by glavanway; 06-20-2011 at 02:36 PM.
Reason: Forgot to add info