Dropping Ref. Integrity - Mailing list pgsql-sql

Hi,

I'm trying to drop some referential integrity on a table and am getting 
this error:

PostgreSQL said: ERROR: zero-length delimited identifier

Your query: DROP TRIGGER "RI_ConstraintTrigger_6187534" ON "host_domain";
DROP TRIGGER "RI_ConstraintTrigger_6187538" ON "host_domain";
DROP TRIGGER "" ON "";


I created this using the 'references' statement.
I dropped the integrity using the PhpPgAdmin tool. There's a screen 
where you can see the triggers on a database.
The 'update' trigger dropped ok but the 'on' trigger is giving the above 
error.

Any idea's ?
TIA
Regards
Rudi.