my first real problem, cash receipt

[ario <..hidden..>]

Hi, I'm trying to input a cash receipt of 1,000 into a list of
outstanding accounts receivable, but something goes wrong.
Here's what I do:

In the list of invoices I select one by clicking the select box, which
shows checked from then on. Then, in the form 'amount' field next to the
checked 'select' box, on the left of which the 'amount' and 'amount due'
both show the number '1,248' , I type '1000' (of course without the
''s).
Then, after clicking 'update', the 'amount' field above the blue
'Invoices' bar, shows the amount I entered: '1,000'.
After clicking 'post' (no matter how many times I clicked on 'update',
because I know that has an 'issue') he (LedgerSMB :) answers with:


DBD::Pg::st execute failed: ERROR: null value in column "chart_id"
violates not-null constraint at LedgerSMB/CP.pm line 426.

Error!

INSERT INTO acc_trans 
(trans_id, chart_id, transdate, 
amount)
VALUES (?, ?, 
?, 
?)
ERROR: null value in column "chart_id" violates not-null constraint


All fields above the blue 'Invoises' bar are properly filled out, except
the 'source' field is left empty by me.

Any suggestion?

thanks