Hi,
Your familiar with BW extractors even though for every issue without single search your posting here.
Please upgrade your self about BW concepts and specially for LO data source extraction.
Once you got the error please do some basic trouble shooting. After that you can post issue here.
Before running RSA3 have you deleted and refilled setup tables? i think not.
fill setup tables and later check at RSA3.
Based on your delta load schedule, you can cross check September month logs.
Are you daily monitoring your delta loads? for your delta loads have you used any alert messages?
if you used then for every failure you may received mail notification as per the settings.
Thanks