Program executed by oli9bw is getting cancelled after processing some documents

I am using a BDC program which reads Sales document No's from MS-Excel and provides mandatory parameters for oli9bw Screen. This job is getting cancelled after inserting 2000 sales doc related records in ECC setup tables.Kindly advise on the following.

1. Why the job is getting cancelled after processing only a few records. Any settings are to be made in ECC to ensure that the job runs for complete set of records given in Excel sheet
2. Presently the job is run in dialog mode.How to schedule this job in the background

Thank you for your response

Hanumanth S