Symptoms:

Batches have a Waiting status at Administration and Monitoring Console and an error appears Failed to add a new batch"

Cause:

This error means you may have 2 similar/identical document definitions that both can be matched with the same image.

Resolution:

Do the following:

1. Use a classifier to distinguish what DocDef it should match to in order to continue.
2. Disable the identical document definition to continue.