HELP WITH POS ON LEDGERSMB 1.2.17

[Walter López <..hidden..>]

Hello, I need , your help to use the
module POINT OF SALE, in ledgersmb 1.2.17, the system works well
until that I try to complete the payment of the opened receipts, the
following message is generated:

DBD::Pg::st execute failed: ERROR:
el valor null para la columna «chart_id» viola la restricción
not null
Error!

INSERT INTO acc_trans 
(trans_id, chart_id, amount, 
transdate, source, memo, cleared)
VALUES (?, (SELECT id FROM
chart
WHERE accno = ?),
?, ?, ?, ?, ?)
ERROR: el valor null
para la columna «chart_id» viola la restricción not null


how i it can solve this problem,
there is some manual that i could read to understand  his utilization
and correct configuration?.


Thank you very much for ,your help