下記のパッチで直りますよ。

diff --git a/lib/Test/Spelling.pm b/lib/Test/Spelling.pm
index 1524966..f7265b7 100644
--- a/lib/Test/Spelling.pm
+++ b/lib/Test/Spelling.pm
@@ -52,6 +52,7 @@ sub pod_file_spelling_ok {
         or croak "Couldn't run spellcheck command '$Spell_cmd'";
     my @words = <ASPELL>;
     close ASPELL or die;
+    unlink $Spell_temp;

     # clean up words, remove stopwords, select unique errors
     chomp for @words;

http://rt.cpan.org/Ticket/Display.html?id=41586