The rrdtool package is putting it's perl modules in this location: /usr/lib/perl5/site_perl/5.8.5/i386-linux-thread-multi/RRDp.pm /usr/lib/perl5/site_perl/5.8.5/i386-linux-thread-multi/RRDs.pm /usr/lib/perl5/site_perl/5.8.5/i386-linux-thread-multi/auto/RRDs /usr/lib/perl5/site_perl/5.8.5/i386-linux-thread-multi/auto/RRDs/RRDs.bs /usr/lib/perl5/site_perl/5.8.5/i386-linux-thread-multi/auto/RRDs/RRDs.so However it should be putting them in the /usr/lib/perl5/vendor_perl/5.8.5/i386-linux-thread-multi/ directory instead. site_perl modules are for locally installed modules (usually not using RPM).
Will be fixed in 1.0.49-3 : I've changed the modules to be installed into vendor_perl instead of the current site_perl.