Warning: Missing argument and other errors

[rathersurf]

I am getting some errors and im not sure exactly what they mean or what to look for. I dont want anyone to do the work for me, I just need help understanding what is going on. I am way to new for alot of the syntax and the errors that come with it. If I knew what to look for and how to fix it I wouldnt post up here, any help or suggestions would be great.

I have already searched this forum, php.net and google and I am still at a loss .

Warning: Missing argument 3 for authenticate_user() in /srv/www/htdocs/dbfunc.php on line 123

Warning: ociparse(): supplied argument is not a valid OCI8-Connection resource in /srv/www/htdocs/dbfunc.php on line 125

Warning: ociexecute(): supplied argument is not a valid OCI8-Statement resource in /srv/www/htdocs/dbfunc.php on line 126

Fatal error: Call to a member function on a non-object in /srv/www/htdocs/dbfunc.php on line 127

[rathersurf]

function authenticate_user($p_LDAP_ID, $p_PASSWORD = '', $conn) {
	$query = "SELECT * FROM teachers T, schools S, stu_enr WHERE T.SCHOOL = S.SCHOOL(+) AND LDAP_ID = '$p_LDAP_ID'";
    $statement = OCIParse($query, $conn);
	$stuff = OCIExecute($statement);
	if($stuff->num_rows() == 0){
		return false;
		} else {
		return $oci->fetch_array();	
		}
	}

The function is line 123 .....