temporal period type and select distinct gives equality error

Hi all,

I'm using the temporal contrib package that creates the period type and
a bunch of operators in postgresql 8.4.5.  I plan to use the same code
against 9.0 so if anything differs between the two regarding this issue
please let me know.

In psql the \do command shows this
 public | =    | period | period  | boolean  |

and yet when I do a select distinct with a join I get

QueryLogger - *** error.
org.postgresql.util.PSQLException: ERROR: could not identify an equality
operator for type period

If I leave the period column out of the select list then it works fine.

Did I install it wrong?  Or is something else going on?

tia
arturo