you probably have sarg 1.x installed
this works fine
the dungog repo has a sarg 2.x version which your yum is finding
but to install sarg 2 you need to enable another repo
from install instructions
yum install --enablerepo=base sarg smeserver-sarg
[note. will also install four dependancies]
you can either
ignore the warning and leave sarg at 1.x, or
disable the dungog repo, or
install sarg 2 with the above command