Transaction suddenly not working

I know recently the server was update from PHP 4.3.8 to 4.3.9 but that shouldn't have effected anything. Code: $query = "INSERT INTO table1 (ProfileID, LurkID, ProfileName, Edu,..................." VALUES (null,......................." ProfileID is the PrimaryID (autoinc) - I've set the input value to null for the auto-inc to properly work. I assume this is correct and it did work at one time. Then before the next query: $LID = mysql_insert_id(); Then each subsequent query uses $LID in the subsequent tables. However $LID is now returning 0 and the transaction fails. At the end of the transaction I follow through with this: //resx = all the queries if($res1 && $res2 && $res3 && $res4 && $res5 && $res6 && res7 ) // If all results are true { commit(); //echo "your insertions were successful"; unset($all session variable, $LID, ); }else{ ................... Puzzling since this script was working great. We did also upgrad MySQL from 4.0.21 to 4.0.22-standard Thank you, Stuart