REQ: Create a sorted table (DAO)

HELP PLEASE, I UPDATE MI BDD IN RED OF THE FOUR USERS, BUT ANOTHER USER GETS
DATA OF THE FIELDS AND NOT IS UPDATED, AND THE DATA IS DUPLICATED IN THE
REGISTER, I USE: DAO 3.6 AND BDD ACCESS 2000 AND VB 6

PLEASE HELP ME:

The database gets up-to-date, but if it(he,she) records the sales in the
same moment the information does not get up-to-date and goes out the records
of sales duplicated (go of sales ...), but if we wait for a moment to record
one after other one there if it works, but if it is recorded to the moment
not ... since I can do???