I was able to do an install no problem on Red Hat 3 - What OS are you trying to install on?
[root@darkstar only-0.28]# perl Makefile.PL
"only.pm" has special functionality that allows you to install multipl
+e
versions of any Perl module. In order to do this, it installs the
modules in a separate directory than the rest of your modules.
You need to decide which directory the modules will be installed in.
This value will be stored in only::config so that only.pm will know
where to look in order to load special versions of a module.
The suggested place to install special versions of Perl modules is:
/usr/lib/perl5/version/5.8.0
Do you want to use the "suggested" directory (y/n)? [y] y
Checking if your kit is complete...
Looks good
Writing Makefile for only
[root@darkstar only-0.28]# make
cp lib/only/config.pm blib/lib/only/config.pm
cp lib/only.pm blib/lib/only.pm
cp lib/only/install.pm blib/lib/only/install.pm
Manifying blib/man3/only.3pm
Manifying blib/man3/only::install.3pm
[root@darkstar only-0.28]# make test
PERL_DL_NONLAZY=1 /usr/bin/perl "-MExtUtils::Command::MM" "-e" "test_h
+arness(0, 'inc', 'blib/lib', 'blib/arch')" t/*.t
t/00config.............ok
t/01install............ok
t/02basic..............ok
t/03range..............ok
t/04clobber............ok
t/05site...............ok
t/06require............ok
t/07inc................ok
t/08use................ok
t/09alternate..........ok
t/10install_version....ok
t/11fail_msg...........ok
t/12set_versionlib.....ok
t/13ooapi..............ok
All tests successful.
Files=14, Tests=54, 1 wallclock secs ( 0.98 cusr + 0.06 csys = 1.04
+ CPU)
[root@darkstar only-0.28]# make install
Installing /usr/lib/perl5/site_perl/5.8.0/only.pm
Installing /usr/lib/perl5/site_perl/5.8.0/only/config.pm
Installing /usr/lib/perl5/site_perl/5.8.0/only/install.pm
Installing /usr/share/man/man3/only.3pm
Installing /usr/share/man/man3/only::install.3pm
Writing /usr/lib64/perl5/site_perl/5.8.0/auto/only/.packlist
Appending installation info to /usr/lib64/perl5/5.8.0/x86_64-linux-thr
+ead-multi/perllocal.pod