Actually the weird behaviour turns out to be due to this (thanks for prompting me to investigate deeper)

    my $is_compressed = $class->gtest($file);
    if ($is_compressed) {
        warn "Its compressed, using a pipe.\n";
        $system = "$CPAN::Config->{gzip} --decompress --stdout " .
            "< $file | $CPAN::Config->{tar} xvf -";
    } else {
        warn "Its not compressed, using tar directly.\n";
        $system = "$CPAN::Config->{tar} xvf $file";
    }
    if (system($system) != 0) {
[download]

When tar.exe is called in the pipe using dos style filespec it works fine. When it is called with unix style paths it chokes with a

'e:' is not recognized as an internal or external command, operable pr
+ogram or batch file.
[download]

And having failed that attempt CPAN tries several variations of gzip and tar before it finally gives up. These variations involve calling tar directly with the filename, which chokes because
So basically tar.exe on Win32 with Cygwin sucks
*ahem* :-)

What a weird error. Anyway, im going to post to the cygwin people to see if anybody has plans to make tar a little more dosprompt friendly.

Thanks for the reply.

--- demerphq
my friends call me, usually because I'm late....