Migration tool - Please specify valid criteria field name

Migration tool - Please specify valid criteria field name

I'm trying to use the Zoho Migration tools to upload a CSV into a form, but everytime i run the command i get:

Please specify valid criteria field name

the command is:

zohocreator.exe upload.csv -authtoken *********** -e AppName -au FormName Asset_Serial Asset_Serial

the first Asset_Serial being the deluge field name and the second being the CSV column name.

at this point i'm stuck because the documentation on the migration tool is mediocre at best so any input here would be great.

Thanks.