Many Zend Guard users developing on OSX 10.7 are facing the problem, where the product cannot be installed.
We produced a package that uses the native OSX disk image for Zend Guard 5.5 installation. The package can be downloaded from this URL:
http://downloads.zend.com/guard/5.5.0/Z ... 5-Lion.dmg
The package can also be used on older Intel-based OSX machines.