help with simple rule

here is the table:

Table "testx"
Attribute | Type | Modifier
-----------+---------+--------------------
starter | integer | not null
second | text | default timestamp('now')

I am trying to make a rule which states:

whenever someone UPDATES starter, UPDATE second with the current
timestamp.

here is my attempt at it:

CREATE RULE testx_update AS ON UPDATE TO testx WHERE (new.starter
<> old.starter) DO UPDATE testx SET "second" = timestamp('now');

here is the error i am recieving:

backend=# update testx SET starter =21910 where second = '10000000';
ERROR: query rewritten 10 times, may contain cycles

here is my plea for help:

help!!! ;) seriously, i haven't been able to get this to work and
i do not know why. any help that anyone can give me would be
greatly appreciated.

TIA,

--ch