Use this to get a file of bad records:
awk 'length < 517' SBN_GIFT_MANIFEST_20130209_234013.TXT > BAD-RECORDS-SBN_GIFT_MANIFEST_20130209_234013.txt
This gives you a quick count:
awk 'length < 517' SBN_GIFT_MANIFEST_20130209_234013.TXT | wc -l

Technical notes, and other ideas.
Use this to get a file of bad records:
awk 'length < 517' SBN_GIFT_MANIFEST_20130209_234013.TXT > BAD-RECORDS-SBN_GIFT_MANIFEST_20130209_234013.txt
This gives you a quick count:
awk 'length < 517' SBN_GIFT_MANIFEST_20130209_234013.TXT | wc -l