blueimp/jQuery-File-Upload — pull request #2450 by anfleurance (2013-07-22 16:45:17+00:00)
Title: NS_ERROR_CANNOT_CONVERT_DATA on form data submition (IE8 / FF9-10)

When I try to upload multipart mixed (JSON + files), I have this error : NS_ERROR_CANNOT_CONVERT_DATA.

After investigation, I found that the problem came from the data submition when field.value is an array.