Many of the "tried and tested" tools of Perl have problems with spaces in directory names, most notably CPAN.pm, and Inline::C (not in the category "tried and tested"). I find this is especialy weird, because under Unix file names with whitespace are much longer allowed than in the Win32 world, and given the Unix-centricity of the developers, this should have been an issue a long time ago. It seems that nobody ever went and fixed the issues. I did once try to hunt down all the cases where CPAN.pm fails to do the Right Thing when (not) quoting filenames, but gave up.

So the moral of this is - don't install Perl below a directory with spaces in its name.