confused big time

hi... i have 2 mysql queries.... first one: //the extra { at the beginning and the extra , at the end of //each variable should be an '... "insert into $EventsTable values(NULL, '{$_SESSION[add][type]}', '{$_SESSION[add][start_date]}', '{$_SESSION[add][end_date]}', '{$_SESSION[add][name]}', '{$_SESSION[add][county]}', '{$_SESSION[add][discription]}', '{$_SESSION[add][StartingDay]}', '{$_SESSION[add][StartingMonth]}', '{$_SESSION[add][StartingYear]}', '{$_SESSION[add][EndingDay]}', '{$_SESSION[add][EndingMonth]}', '{$_SESSION[add][EndingYear]}'"; and the other one: "insert into $GuestbookTable values(NULL, '{$_SESSION[add][date]}', '{$_SESSION[add][name]}', '{$_SESSION[add][email]}', '{$_SESSION[add][website]}', '{$_SESSION[add][referred]}', '{$_SESSION[add][comments]}')"; they both use the same identical format to insert the arrays. there is an interesting problem though: the first one complains about use of undefined constant add - assumed 'add' in the second query...the first one doesnt do that?? everything is set up exactly the same for both queries except the relevant variable/array names...