v7.0.2: can't use 'EXTRACT(EPOCH FROM'

I'm running postgres 7.0.3 on one machine and 7.1.2 on another.  I tried
running the exact SQL sample from the user manual for date time
functions:

SELECT EXTRACT(EPOCH FROM TIMESTAMP '2001-02-16 20:38:40');

This example won't run on the v7.0.3 and I get teh following error:

ERROR:  parser: parse error at or near "epoch"

However, the same SQL sample runs on v7.1.2.  Am I doing something wrong
here? Is this a known bug?