you have made 2 mistakes.
1st, if you want to use php function mysql_insert_id(). You should pass a link identifier in it, just like vincent said.
sample code should be like that:
#######################
$linkid = mysql_pconnect("server", "user", "password") or die(); //make connection
mysql_select_db("database", $linkid); // select table
$sql = "INSERT INTO sometable VALUES (somevalue)"; // query sql
$queryid = mysql_query ($sql, $linkid) or die(); //make query
$new_id = mysql_insert_id($linkid); // make clear that it is $linkid, not $queryid
.
.
.
###########################
2nd, if you wanna to use a query to get the last insert id from mysql you should use 2 query like that:
###########################
//make db connection & select database
...
// insert value
$insert_sql = "INSERT INTO sometable VALUES (somevalue)";
$queryid = mysql_query ($insert_sql, $linkid) or die(); //make insert query
$getlastid_sql = "SELECT LAST_INSERT_ID() as id";
$queryid = mysql_query ($getlastid_sql, $linkid) or die(); //make get last insert id query
list($newid) = mysql_fetch_array($queryid);
...
##############################