I cannot understand why WWW::Mechanize::Sleepy does not find WWW::Mechanize on my machine.

Compiling from Scratch

root@jasmines:/usr/local/src/WWW-Mechanize-Sleepy-0.5# perl Makefile.P
+L

If you are testing:
- for 'make test' to work you must be connected to the Internet
- expect 'make test' to take some time since it tests sleepiness

Warning: prerequisite WWW::Mechanize 0.58 not found.
Writing Makefile for WWW::Mechanize::Sleepy
root@jasmines:/usr/local/src/WWW-Mechanize-Sleepy-0.5# locate Mechaniz
+e.pm
/usr/lib/perl5/site_perl/5.8.0/WWW/Mechanize.pm
[download]

One-liner to Test

root@jasmines:/usr/local/src/WWW-Mechanize-Sleepy-0.5# perl -wle 'use 
+WWW::Mechanize 99'
WWW::Mechanize version 99 required--this is only version 1.18 at -e li
+ne 1.
BEGIN failed--compilation aborted at -e line 1.
[download]

Version 1.18 should be sufficient, right?

I've tried everything. Other modules are failing to install for CPAN for similar reasons. What might cause something like this?