Large text fields in the database

I am using the RPM packaged postgreSQL server 7.1.3 which is
shipped with RH 7.2.

The problem I have is the size of text fields. Although in Documentation
it clearly says that the DB supports text fields larger than 8Kb, I am
unable to insert or update fields (and tables for that matter) with data
larger than 8Kb.

Whenever I try to do that, I get unresolved symbol SPI_lastoid in
plpgsql.so

Can anyone help me with this - several friends suggested that I should
recompile the DB from source, and enable the large tuples, but I looked
in the source and it clearly says it's supported in this version.

Best regards,
alex.