the first thing is that postgres needs several dependencies
bash-3.2# rpm -i pgdg-redhat91-9.1-5.noarch.rpm
warning: pgdg-redhat91-9.1-5.noarch.rpm: Header V4 DSA signature: NOKEY, key ID 442df0f8
error: Failed dependencies:
        rpmlib(FileDigests) <= 4.6.0-1 is needed by pgdg-redhat91-9.1-5.noarch
        rpmlib(PayloadIsXz) <= 5.2-1 is needed by pgdg-redhat91-9.1-5.noarch

then I found an rpm that has the dependencies but then it too has dependencies
bash-3.2# rpm -i rpm-libs-4.7.2-2.fc12.x86_64.rpm
warning: rpm-libs-4.7.2-2.fc12.x86_64.rpm: Header V3 RSA/SHA256 signature: NOKEY, key ID 57bbccba
error: Failed dependencies:
        libcap >= 2.16 is needed by rpm-libs-4.7.2-2.fc12.x86_64
        libcap.so.2()(64bit) is needed by rpm-libs-4.7.2-2.fc12.x86_64
        libdb-4.7.so()(64bit) is needed by rpm-libs-4.7.2-2.fc12.x86_64
        liblua-5.1.so()(64bit) is needed by rpm-libs-4.7.2-2.fc12.x86_64
        liblzma.so.0()(64bit) is needed by rpm-libs-4.7.2-2.fc12.x86_64
        libpopt.so.0(LIBPOPT_0)(64bit) is needed by rpm-libs-4.7.2-2.fc12.x86_64
        rpm = 4.7.2-2.fc12 is needed by rpm-libs-4.7.2-2.fc12.x86_64
        rpmlib(FileDigests) <= 4.6.0-1 is needed by rpm-libs-4.7.2-2.fc12.x86_64
        rpmlib(PayloadIsXz) <= 5.2-1 is needed by rpm-libs-4.7.2-2.fc12.x86_64

errrrr
finally went to http://www.openscg.org/se/postgresql/packages.jsp
and ran rpm -i postgres-9.1.1-1.x86_64.openscg.rpm
B

and it seemed to install. we'll see