Mass Update script overdue balance email not working - sss_invalid_cc_email

I'm trying to get a massupdate script to email all customers with a balance > 0.  As far as I know I can't use the "Sending Collection Letters in Bulk" in the help because we also need to send the statements to the contacts on that customer.  We have a checkbox to control if a contact receives statements or not.  The mass update criteria is as follows:

Do not email statement (custom) is false
Balance > 0

I've tried to run the mass update and it seems to send to 5 customers or so before failing with the error sss_invalid_cc_email.  I then thought we could be attaching empty email addresses in the cc array.  I tried to check for blank strings but it doesn't seem to be working.  Here is our script (sorry for all the debug statements just trying to figure out why it's not working):