You are unable to open a file with a .ppz file name extension by using Microsoft Office PowerPoint 2007.
A .ppz file could be a PowerPoint animation file (a streaming format intended for Web use rather than for exchanging presentations with others), but most likely it is a packaged PowerPoint file created by the Pack and Go Wizard. The Pack and Go Wizard is not available or supported in Office PowerPoint 2007.
To copy your Office PowerPoint 2007 presentation to a CD, a network, or a local disk drive on your computer, see Copy a presentation to a CD, network, or local disk drive.
In PowerPoint 2002 and earlier, the Pack and Go Wizard made it possible to package one or more presentations, including linked files and embedded fonts, into a single .ppz file. In addition, the Pack and Go Wizard would create a file called pngsetup.exe that allowed the recipient of the two files to unpackage the .ppz file. Without the pngsetup.exe file, a Windows file compression tool such as WinZip would be required to open the .ppz file.
To learn to work with files created by the Pack and Go Wizard, see the Knowledge Base article How to use the Pack and Go feature in PowerPoint 2000 or PowerPoint 2002.