Getting this error while processing lockbox file: Receipt has invalid applications

While trying to process a sample lockbox file, I am facing the errors:

1. Receipt has invalid applications and

2. You must enter a valid overflow record for this receipt

Does invoice no. really needs to be valid to import receipts. It should be created in Unapplied status if invoice no. is not valid. Any comments on this beahvior please?

Also, I am not clear with 2nd error. All records have same structure in file but only 2 receipts got created that does not have Invoice no. or record 4 itself was missing. What is the standard behavior here.

Regards

Deepak