When accounting has been created successfully in Oracle Payables and then send to GL interface table, for example, is it possible that something could blocks the import to GL production tables, when all related periods in Oracle Payables are also opened in GL when the import program takes place?
What could that be, for instance, which could make other data still sitting in the interface table after the import program is run?

There could be various things. Common problems:
* An account has been disabled by GL users afterwards (before the GL import).
* A combination has been disabled.
* Cross validation rules are in place.
* Period is now closed.
* Intercompany entries are not balanced. E.g. DEBIT: 01-5000, CREDIT 02-5000

Thank you very much Hasan.
1) How would I know the nature of the problems of the data the Interface table failing the import program?
2) Is there a report output to view, which would indicate the nature of the import failure, example, id cross Validation is what is causing the problem?
3) At what circumstances do we need to cancel the whole transfer from the subledger (that is deleting the data in the Interface table)?
4) Or, do we have to fix all the problems no matter the number of transactions failing the import?

1) View the out of journal import program
2) Yes see 1)
3) There are various ways of dealing with the issues. Ideally you let every thing come in to GL. Then fix the core issues in subledgers (e.g. cancel bad invoices/payments and resubmit the corrections to GL again.) Also read more on suspense accounts.
4) You only fix the error lines.
I thought I addressed these questions in category 16: http://handsonerp.com/oracle-financials-tutorials/69-15-interfaces.html

Thanks Hasan. I think I have read somewhere that if there are a very high level of problem lines in the GL interface table, the best thing to do is to delete the whole data in the GL interface table, go back to the subledger and fix the problem and then resubmit the transafer to GL program. Does it make sense at all? How do you delete the data in the GL interface table?

You can do that easily in case of custom applications sending data to GL. When you run AP to GL transfer, the data in AP is marked as transferred, even if it is still sitting in GL interface table. You can delete the data in the interface table by running the SQL command: delete from gl_interface; However that will not reset the transfer flag in AP. You will need to do some other back end tweaking (updates to ap_ae_headers etc) to reset the flag, which is not recommended. Once the data leave AP, it is recommended that it should flow all the way to GL. This is also important for clean reconciliation.

What I said above is true for 11i. In R12 the accounting is managed by SLA as oppose to AP. Once you run the transfer to GL, SLA marks the data as transferred. Same logic applies.

Thank you, Hasan.