Download latest dahdi-linux from http://downloads.asterisk.org/pub/telephony/dahdi-linux/
Follow theses instructions and have the modules...
Then after that try the normal:
yum -y install dahdi-tools kernel-devel kernel-headers
I could be wrong on that last part, but the instructions for it are in the readme in the packages folder.
cd dahdi-linux* ./configure make distclean make make install all