jatar_k - 8:13 pm on Nov 7, 2011 (gmt 0)

it means there is a syntax error, you could also spit out $query and look at it and see if it is properly constructed. Maybe one of the vars is not resolving properly

also is the id column an integer (I think you said it was alpha)? if not then it needs single quotes around the value
$query = "SELECT contactid from $table_name where id='$id'";