When I ran your code, using Devel::Cover, I got the following on Devel::Cover 0.40, Perl 5.8.1 rc3, on OS X 10.3.5. What do you see?

% perl -MDevel::Cover 1.t
Devel::Cover 0.40: Collecting coverage data for branch, condition, sta
+tement, subroutine and time.
Pod coverage is unvailable.  Please install Pod::Coverage from CPAN.
Selecting packages matching:
Ignoring packages matching:
Ignoring packages in:
    .
    /Library/Perl
    /Library/Perl/5.8.1
    /Library/Perl/5.8.1/darwin-thread-multi-2level
    /Network/Library/Perl
    /Network/Library/Perl/5.8.1
    /Network/Library/Perl/5.8.1/darwin-thread-multi-2level
    /System/Library/Perl/5.8.1
    /System/Library/Perl/5.8.1/darwin-thread-multi-2level
    /sw/lib/perl5
1..4
ok 1 - use abcd;
ok 2
ok 3
ok 4
Devel::Cover: Writing coverage database to /Users/paul/monks/cover_db/
+runs/1092444838.2071.64541
----------------------------------- ------ ------ ------ ------ ------
+ ------
File                                  stmt branch   cond    sub   time
+  total
----------------------------------- ------ ------ ------ ------ ------
+ ------
1.t                                  100.0    n/a    n/a    n/a   90.9
+  100.0
abcd.pm                              100.0  100.0    n/a  100.0  100.0
+  100.0
Total                                100.0  100.0    n/a  100.0  100.0
+  100.0
----------------------------------- ------ ------ ------ ------ ------
+ ------
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