I tried version 2 and the development version.
Did you get them on sale at WalMart? If so, take them back. If not, you might want to mention some things like where you got them, which version of the IDE you are using, which Arduino you are compiling for, and which OS you are using. Oh, and POST YOUR CODE!
Someone was just complaining about this recently, and actually posted a link. I downloaded the library at that link and when I compile the Ping.ino example, I only get one "error":
Binary sketch size: 9,374 bytes (of a 32,256 byte maximum)