Forum OpenACS Q&A: Response to RedHat 7.1 RPM errors
It sounds as though PG 7.0.3 was not the only thing you somehow installed by accident! A little more attention to detail during the installation of your OS would probably have bene helpful?
Anyway, now the basic issue becomes, do you need all of that stuff which rpm says is dependent on PG 7.0.3, or not? Do you use any of it? If not, then just uninstall it with rpm -e whatever . If you are really using PHP with PG drivers, and/or the Perl DBD interface to PG, then you are already using PG 7.0.3, so stop and think before you remove PG 7.0.3 and related software.
If you need to check what a particular rpm that is installed is for, because you are unfamiliar with it, the command rpm -qi rpmname will display a brief summary about the package.