On my CentOS 6 box, DynaLoader.pm is found at /usr/lib64/perl5/DynaLoader.pm and since /usr/lib64/perl5 is reported to be in your @INC, you should be finding it. This file is part of the "perl" rpm, so if you have perl installed (via yum) but DynaLoader.pm is missing then it's likely that something has gone badly wrong with your system.