cache Issue with content module in CCK

hi ,
i created 3 CCK fields on user registration page. One is for Country & second one is state(Drop down box), third one again for state(Text box) . According to Country, state should be change in second state filed. if no state available for any country, then state drop down box will be hide & state (Text box) will be populate. i did it via JavaScript.Now My problem is that In Country CCK field i put code

query = 'SELECT DISTINCT country from {statelist} order by country ASC';
$result = db_query($query);
$country= array();
while($row = db_fetch_object($result))
{
$country[$row->country]=$row->country;
}
return $country; 

& for state drop down box

$query = 'SELECT DISTINCT state from {statelist} order by state ASC';
$result = db_query($query);
$state= array();
while($row = db_fetch_object($result))
{
$state[$row->state]=$row->state;
}
return $state;

when i going to submit PHP code for state drop down. whole site gone away. i got blank pages. after clearing cache & state drop down box code from database(node_field), everything seems to be work. but state drop down is not working, when i go for submit the user.
When i submit to PHP code in state CCK field, Problem has been started. so what can be problem?
Please guide me

Best,
Kamlesh