[X4U] UNARCHIVE question

[Ed Gould]

I downloaded a zip file from a web site. I put it on my desktop and  
double clicked it and I got a message saying:
UNABLE TO UNARCHIVE this.zip  into the desktop error1-Operation not  
permitted.

I moved it to a subfolder and received essentially the same error  
message (except the location)

I have downloaded it twice and I got the same message. Is the file  
corrupt? (why doesn't it say so?).

ANy hints or ideas would be appreciated.

Ed