Can't migrate any field data to D7 from D6

I'm currently working on converting a clients Drupal 6 site over to Drupal 7. The actual upgrade process works fine, and I can successfully migrate the field structure over for each of my custom fields. However, no matter what I do I can't seem to get any of the field data to go with it. On the content migrate page each of my fields are displaying information like:

Invalid field/widget combination: The field 'field_featimgcredit' in the bundle 'lavender_lens' is an unlimited length field using a textfield widget, not allowed in D7. The field length will be set to 255.
Missing formatter: The 'text_hidden' formatter used in 4 view modes for the field_featimgcredit field is not available, these displays will be reset to the default formatter.
Missing formatter: The 'text_hidden' formatter used in 4 view modes for the field_featimgcredit field is not available, these displays will be reset to the default formatter.
Missing formatter: The 'text_hidden' formatter used in 4 view modes for the field_featimgcredit field is not available, these displays will be reset to the default formatter.
Missing formatter: The 'text_hidden' formatter used in 2 view modes for the field_featimgcredit field is not available, these displays will be reset to the default formatter.
Missing formatter: The 'text_hidden' formatter used in 4 view modes for the field_featimgcredit field is not available, these displays will be reset to the default formatter.
Missing formatter: The 'text_hidden' formatter used in 2 view modes for the field_featimgcredit field is not available, these displays will be reset to the default formatter.

And after every attempt I get an AJAX error like the following:

An AJAX HTTP error occurred. HTTP Result Code: 500 Debugging information follows. Path: /batch?id=766&op=do StatusText: error ResponseText: {"status":true,"percentage":"50","message":"Processed 1 out of 2.\u003Cbr \/\u003EProcessing through nid \u003Cem class=\u0022placeholder\u0022\u003E118\u003C\/em\u003E"}

I've also attempted migrating using drush as well but still get errors.

Not even basic text fields will transfer data over. This is also a particularly large site as well containing about 17k+ nodes. Any ideas?