The install scripts depends on new features introduced in the Installer delivered with OS 3.5. While the version delivered with OS 3.1.4 is 45.6, it is derived from OS 3.1 and therefore misses the extensions of the OS 3.5 release. The version of the Installer reported to scripts is 43.xx.
You may either ignore this warning: the installation will still work without using the features of the OS 3.5 Installer, or you may get the Installer from OS 3.5 which will work on the OS 3.1.4 system too (including some bugs which got fixed in the OS 3.1.4 release). The missing features of the Installer may appear in a future release of the OS.
