It looks like an error. ( Full Response: 3:: )
The following defines Authorize.net FULL TEXT responses...
Primer: The first digit: "**1**":1:1:This transaction has been approved
1 = approved
2 = declined
3 = error
4 = under review
I would recommend logging into your Authorize.net Control panel in TESTMODE and the online Chat option will provide you with really quick support. I recall having trouble myself with sending too much data to specific fields which can not accept large amounts of data. You must be very cautious with what you're sending to them.