Troy, libxml binary RPMs compiled for RH 7.1 do not seem to exist,
even at the official home of libxml.
Solution: obtain the libxml2 source RPM and rebuild it on your RH 7.1
machine, then install the newly created libxml2 binary RPM.
I'll probably do this and stick a libxml2 binary RPM for RH 7.1 on my
site any day now ... but until then, grabbing the source RPM and doing
rpm --rebuild libxml2-2.3.8-1.src.rpm
should work.
I have not tried these RPMs with any version of PG except PG 7.1 so far.