Long time reader, first time poster. Big, appreciative thanks for everyone's collective questioning and answering here and at stackoverflow, it's helped me quite a lot over the time I've been learning answers through these sites! Apologies in advance if I didn't search hard enough on posts already up on this site to find out what I could do about this issue, but I thought I'd just reach out for the sake of trying at least once.

I've experienced this issue while starting up my macports-installed version of irssi:

13:25 -!- Irssi: Error in script dispatch:
13:25 Can't locate lib.pm in @INC (@INC contains: 
      /opt/local/lib/perl5/site_perl/5.12.4/darwin-multi-2level 
      /opt/local/lib/perl5/site_perl/5.12.4 
      /opt/local/lib/perl5/vendor_perl/5.12.4/darwin-multi-2level 
      /opt/local/lib/perl5/vendor_perl/5.12.4 
      /opt/local/lib/perl5/5.12.4/darwin-multi-2level 
      /opt/local/lib/perl5/5.12.4 
      /opt/local/lib/perl5/site_perl/5.12.3/darwin-multi-2level 
      /opt/local/lib/perl5/site_perl/5.12.3 /opt/local/lib/perl5/site_perl 
      /opt/local/lib/perl5/vendor_perl .) at (eval 18) line 1.
13:25 BEGIN failed--compilation aborted at (eval 18) line 1.
13:25 

Huh, strange. I looked into it a bit:

[email protected] /opt/local/lib/perl5  
?- find . -name "lib.pm" -ls
14673887           16 -r--r--r--    1 root     admin        6853 25 Jun 23:39 ./5.12.4/darwin-thread-multi-    2level/lib.pm

[email protected] /opt/local/lib/perl5  
?- l 5.12.4/darwin-thread-multi-2level 
total 1864
drwxr-xr-x   55 root  admin    1870 28 Jun 19:28 .
drwxr-xr-x  158 root  admin    5372 28 Jun 19:28 ..
-rw-r--r--    1 root  admin  177814 25 Jun 23:39 .packlist
drwxr-xr-x    6 root  admin     204 28 Jun 19:28 B
-r--r--r--    1 root  admin   25714 25 Jun 23:39 B.pm
drwxr-xr-x   64 root  admin    2176 28 Jun 19:28 CORE
drwxr-xr-x    3 root  admin     102 28 Jun 19:28 Compress
-r--r--r--    1 root  admin    3000 25 Jun 23:39 Config.pm
-r--r--r--    1 root  admin  228094 25 Jun 23:39 Config.pod
-r--r--r--    1 root  admin     409 25 Jun 23:39 Config_git.pl
-r--r--r--    1 root  admin   38759 25 Jun 23:39 Config_heavy.pl
-r--r--r--    1 root  admin   21174 25 Jun 23:39 Cwd.pm
-r--r--r--    1 root  admin   63535 25 Jun 23:39 DB_File.pm
drwxr-xr-x    3 root  admin     102 28 Jun 19:28 Data
drwxr-xr-x    5 root  admin     170 28 Jun 19:28 Devel
drwxr-xr-x    4 root  admin     136 28 Jun 19:28 Digest
-r--r--r--    1 root  admin   25185 25 Jun 23:39 DynaLoader.pm
drwxr-xr-x   22 root  admin     748 28 Jun 19:28 Encode
-r--r--r--    1 root  admin   29731 25 Jun 23:39 Encode.pm
-r--r--r--    1 root  admin    6736 25 Jun 23:39 Errno.pm
-r--r--r--    1 root  admin    5445 25 Jun 23:39 Fcntl.pm
drwxr-xr-x    5 root  admin     170 28 Jun 19:28 File
drwxr-xr-x    3 root  admin     102 28 Jun 19:28 Filter
-r--r--r--    1 root  admin    1819 25 Jun 23:39 GDBM_File.pm
drwxr-xr-x    4 root  admin     136 28 Jun 19:28 Hash
drwxr-xr-x    3 root  admin     102 28 Jun 19:28 I18N
drwxr-xr-x   11 root  admin     374 28 Jun 19:28 IO
-r--r--r--    1 root  admin    1404 25 Jun 23:39 IO.pm
drwxr-xr-x    6 root  admin     204 28 Jun 19:28 IPC
drwxr-xr-x    4 root  admin     136 28 Jun 19:28 List
drwxr-xr-x    4 root  admin     136 28 Jun 19:28 MIME
drwxr-xr-x    3 root  admin     102 28 Jun 19:28 Math
-r--r--r--    1 root  admin    2519 25 Jun 23:39 NDBM_File.pm
-r--r--r--    1 root  admin    4208 25 Jun 23:39 O.pm
-r--r--r--    1 root  admin   15563 25 Jun 23:39 Opcode.pm
-r--r--r--    1 root  admin   21011 25 Jun 23:39 POSIX.pm
-r--r--r--    1 root  admin   58962 25 Jun 23:39 POSIX.pod
drwxr-xr-x    5 root  admin     170 28 Jun 19:28 PerlIO
-r--r--r--    1 root  admin    2515 25 Jun 23:39 SDBM_File.pm
drwxr-xr-x    4 root  admin     136 28 Jun 19:28 Scalar
-r--r--r--    1 root  admin   10837 25 Jun 23:39 Socket.pm
-r--r--r--    1 root  admin   41003 25 Jun 23:39 Storable.pm
drwxr-xr-x    4 root  admin     136 28 Jun 19:28 Sys
drwxr-xr-x    3 root  admin     102 28 Jun 19:28 Text
drwxr-xr-x    5 root  admin     170 28 Jun 19:28 Time
drwxr-xr-x    3 root  admin     102 28 Jun 19:28 Unicode
-r--r--r--    1 root  admin   14462 25 Jun 23:39 attributes.pm
drwxr-xr-x   38 root  admin    1292 28 Jun 19:28 auto
-r--r--r--    1 root  admin   19892 25 Jun 23:39 encoding.pm
-r--r--r--    1 root  admin    6853 25 Jun 23:39 lib.pm
-r--r--r--    1 root  admin   11044 25 Jun 23:39 mro.pm
-r--r--r--    1 root  admin     997 25 Jun 23:39 ops.pm
-r--r--r--    1 root  admin   13945 25 Jun 23:39 re.pm
drwxr-xr-x    3 root  admin     102 28 Jun 19:28 threads
-r--r--r--    1 root  admin   33283 25 Jun 23:39 threads.pm

So, it sort of seems to me that the permissions which perl5 got installed with for these modules has gotten mixed up somehow? I'm not really a perl user beyond enjoying it for massive directory-recursive find/replace operations within text files, so I haven't much of an idea what the permissions here are supposed to look like, and I'm not really sure how to go about determining how macports has gone and installed perl this way when it's otherwise worked without failure for years now. Does anyone have any recommendations for the sanest path towards rectifying this issue? Also, is there any interesting reason as to why the macports default for the perl5 port installs 5.12.4, and not 5.16.0, which has to be explicitly installed via the perl5.16 port?

Thanks again!