I have used CPAN to install perl modules on quite a few occasions, but I've been lucky enough to just have it work. Unfortunately, I was trying to install Thread::Pool today and one of the required dependencies, Thread::Converyor::Monitored failed the test:

Test Summary Report
-------------------
t/Conveyor-Monitored02.t (Wstat: 65280 Tests: 89 Failed: 0)
  Non-zero exit status: 255
  Parse errors: Tests out of sequence.  Found (2) but expected (4)
                Tests out of sequence.  Found (4) but expected (5)
                Tests out of sequence.  Found (5) but expected (6)
                Tests out of sequence.  Found (3) but expected (7)
                Tests out of sequence.  Found (6) but expected (8)
Displayed the first 5 of 86 TAP syntax errors.
Re-run prove with the -p option to see them all.
Files=3, Tests=258,  6 wallclock secs ( 0.07 usr  0.03 sys +  4.04 cusr  1.25 csys =  5.39 CPU)
Result: FAIL
Failed 1/3 test programs. 0/258 subtests failed.
make: *** [test_dynamic] Error 255
  ELIZABETH/Thread-Conveyor-Monitored-0.12.tar.gz
  /usr/bin/make test -- NOT OK
//hint// to see the cpan-testers results for installing this module, try:
  reports ELIZABETH/Thread-Conveyor-Monitored-0.12.tar.gz
Running make install
  make test had returned bad status, won't install without force
Failed during this command:
 ELIZABETH/Thread-Conveyor-Monitored-0.12.tar.gz: make_test NO

What steps do you take to start seeing why an installation failed? I'm not even sure how to begin tracking down what's wrong.