OK, i recently was having some nightmare with perl, I installed perl from source, but left my rpm install intact, messed around for a week, and eventually went back to the rpm. Bottom line is, I did this on the ~/src/nagios-plugins-1.4 as you may have.
and got this for output
Can't locate Cache.pm in @INC Plus a mess of other lines.
I then did this
perl -MCPAN -e 'install Cache::File'
with no errors but it hung during some snmp check, so running make install should be no trouble since everthing did compile.