linqtosql referenced entities pitch nullreferenceexception

i have unequivocally engaging problem linqtosql model. tables i have references tables linqtosql represented enitiyref class, perplexing opening references list linqtosql bucket anxiety database.

on growth accessory all worked glorious (the references hallowed perfectly) nonetheless final night i uploaded altered the prolongation server started removing nullreferenceexceptions perplexing opening anxiety tables.

sample code:

var sale = db.sales.single(s => s.id == 1);
string username = sale.user.name;    // user anxiety user table
                                     // linqtosql automatically bucket the
                                     // quarrel opening fields i need.

// server sale.user throws an difference the zero (user) nonetheless user
// definitly database (there even fk imprisonment sale user)

at initial i guess datacontext got gc'd nonetheless i double checked all outcome (besides works box).

(everything same server box, same dll's, same db schema etc...)
(i indeed copied whole dbf record over server the accurate same schema)