Because RH 6.2 is old now, and Postgres requires newer libraries. If possible you would be better off upgrading RedHat first; at this point upgrading libraries is a real PITA. Each of those probably requires five others to be upgraded, each of which will need other things upgraded, etc etc.
If you can't upgrade, you can probably compile Postgres from source without upgrading your libraries. It's just the RPM version, which is precompiled, that requires updates. But I haven't done this on a non-updated 6.2 in quite a while, so I can't promise you that it works!
FYI, in the future please wrap your text blocks in pre tags; it's hard to read this way.
