pg_dumpall and version confusion

I inherited an existing system with no documents on how it was originally
configuerd, so I'll provide as much as I can. OS is CentOS 4.3 Linux
Distribution.

When I search my system for anything postgres I find a boatload of 8.0.4
source, and a boatload of 7.4.8 documentation.

postgres --version yields 8.1.4 (thats no typo)
psql --version yields 7.4.8
pg_dump --version yields 7.4.8
pg_dumpall --version yields 7.4.8

When doing 'which' on all of the above binaries I get /usr/bin/____ for all
4.

The original problem was recieving 'pg_dumpall: query failed: ERROR:
column "datpath" does not exist' error when trying to run pg_dumpall. I
learned that this is expected error if pg_dumpall is too new for the
database, but it claims to be 7.4.8. I hate to ask a terribly vague
question but how do I find out what version I'm running when postgres and
psql don't agree? There's no trace of 8.1.4 files on the system so I'm
without a lead as to how I have a binary for it.

Thanks for any assistance you can provide.