createuser error

Hi, I'm new to databases.

I'm using version 7.4 on Red Hat Enterprise Linux 3. I'm trying to install sql-ledger featured in a recent article in Linux Journal. Postgres is running, and I haved initialized the database. The next step seems to be creating the program user. My instructions say to :

# su postgres
$ createuser -d sql-ledger

I get this error:

createuser: relocation error: createuser: undefined symbol: get_progname

I don't really know where to go from here.

Thanks,
Dan Thompson