Problem installing XCode 2.5 on Tiger

If you find the XCode 2.5 won't install for you it could be you have a similar problem as I've just had.

Symptom:
The XCode installer bounces briefly, and dies.
In the console log there's the message:

Can't locate Foundation.pm in @INC (@INC contains: /System/Library/Perl/5.8.6/darwin-thread-multi-2level /System/Library/Perl/5.8.6 /Library/Perl/5.8.6/darwin-thread-multi-2level /Library/Perl/5.8.6 /Library/Perl /Network/Library/Perl/5.8.6/darwin-thread-multi-2level /Network/Library/Perl/5.8.6 /Network/Library/Perl .) at /Volumes/Xcode Tools/Installers/Xcode Installer Launcher.app/Contents/MacOS/XcodeInstallerLauncher line 3.
BEGIN failed--compilation aborted at /Volumes/Xcode Tools/Installers/Xcode Installer Launcher.app/Contents/MacOS/XcodeInstallerLauncher line 3.

Solution:
The missing Foundation.pm appears not to be in the library path for /usr/bin/perl. Its actually in /System/Library/Perl/Extras, so the simple solution is to do the following on the command line...

mirror-doors:~ cloud$ export PERL5LIB=/System/Library/Perl/Extras
mirror-doors:~ cloud$ /Volumes/Xcode\ Tools/Installers/Xcode\ Installer\ Launcher.app/Contents/MacOS/XcodeInstallerLauncher