Please do not put an Eclipse installation into the program files folder. Historically Eclipse has been designed for in-place self-modification, but the "Program Files" folder is not writable for normal users. Use a folder instead, which can be written to by any user, e.g. something like c:\eclipse.
Side note: Most eclipse functionality works fine even in a non writable directory, as Eclipse will store the configuration information at a different location then. But not all plugins have been designed and crafted with this in mind.