I haven't ran into that.
You can look/view at the errored entries by looking at the ART database Tbl_billing_error table in SQL Enterprise manager though, or query all records in that table.
I haven't been able to find a cisco doc explaining errors yet. I did run into the CDR system error report, 'directory number is negative'. This means that the calling party # was null.
I don't think errored entries are put into CDR database (maybe just some of them)?. I can't recall if the ART Error table has error in it offhand either.