error # 1054

I get this error when trying to access the recordset in the bindings.

Full error is MySql Error # 1054

Unknown column  'sessionuser' in 'on clause'

The sql is

SELECT  advert.advert_id, advert.o_make, advert.o_model, advert.w_make, advert.w_model, offer.offer_id, offer.from, offer.to,

advert_1.advert_id x, advert_1.o_model y, advert_1.o_make z

FROM (advert  LEFT JOIN  offer ON advert.advert_id = offer,to)

INNER JOIN members m  ON advert.user_id = m.user_id AND m.username = sessionuser

LEFT JOIN advert as advert_1 ON offer.from = advert_1.advert_id

I have the sessionuser variable set up a text, default value -1, runtime value $_SESSION['MM_Username']

The sql 'test' works fine.

Once I entered the values manually in the code view, the code worked fine.

The code works when i run it live also, correctly displaying records based on sessionuser.

But the question remains, why can't I access the bindings?

The strange thing is it was working Ok yesterday.