This error indicates a problem with the export Schema of the Job. There are two possible solutions:

1.    If you are technically inclined and don’t want to lose the export schema, you can manually edit the schema file to fix it.
    a.    Go to Tools | Configuration Data…
    b.    Find the file(s) that end with _Schema.xml. One of those files is the schema for the job that is failing. You can figure out which is the correct _Schema.xml file either by opening the Job.xml file and comparing the JobID field to the first part of the Schema file name, or by just opening each _Schema.xml file and seeing which one is correct.
    c.    Edit the values inside the <Column></Column> tags by opening the _Schema.xml file in Notepad. The values should go from 0 on up and must not repeat. The first five values (Column 0 to 4) are internal fields required by the program. Values 5 on up are for user defined fields.

2.    You can delete the problem schema and re-create it in the program.
    a.    Find the correct _Schema.xml file as in steps a and b above and delete it.
    b.    Re-create the export schema by opening the job and building it again.