Tried to install Postgres 8.0.1RPM on SME Server 6.0.1 using IWells' instructions based on installing Postgresql 7.4.2.
Could not start postgres. The log file states missing "libssl.so.4".
You shouldn't be able to install RPMs when the system is missing necessary libraries like that. Did you by any chance use --nodeps or --force when installing the RPM? If you did, you've now learnt why you shouldn't do that.
You don't say where you got your Postgres 8.0.1 RPM from, but I'm sure it's not compiled to work with RedHat 7.3. Grab the postgres RPMs from RH 7.3 (or FedoraLegacy 7.3) and you won't have this problem.