Does the JEDP Theory propose that the Scriptures are not inerrant/inspired?
JEDP is scholarly theory on the history and development of the Scriptures. It focuses on the internal structure of the documents while keeping in mind the context of the writing. The analysis treats them as if they are just like any other texts. The authors' motives, culture, etc are considered.
This means that while analysing the documents, inspiration is not assumed. Traditions about the authorship are ignored or taken as just one input. This had a significant effect when attempting to date the texts. It is assumed that texts were written after the events they describe. No clear prophesy of historical events.
Note however, that this does necessarily exclude inspiration. There are many textual critics who accept JEDP (or another version) but also accept the inspiration of the Scriptures. They tend to emphasize the inspiration of the process of the development of the document, the writing of the sources, the selection of sources, the redaction of sources.
Pete Enns is one such scholar who as achieved some notoriety professing this view. His blog and more so his books provide an accessible introduction.