Invalid data was returned to us from SuccessWare21.
There is a bad character in the assignment. If you can find the invalid character in the assignment and remove it, this will clear up the issue.
If you can't get past this error, please give our Support team a call at 1-800-566-6940. We'll work with you and SuccessWare21 support to find out where the bad data originated from so that it can be changed in SuccessWare21.