Nice plugin. I had a CSV 2 POST premium user request that I provide schema support. It would be in an auto-blogging fashion so users would need to pair up columns of data with each attribute in the scheme.
New to schema myself so I started with your plugin.
[schema type="null" ]
It led to some troubleshooting and I discovered these lines to be the cause...
They also cause the media up-loader to return failure and a lot of users are having that issue right now. Might be one of the causes, hopefully it is the only cause.
Anyway I thought I would help you out.
I'm looking at your plugin and considering integration then promoting your plugin along with CSV 2 POST. Makes more sense to integrate it and not have another author managing the schemas right. However I need to figure out what my users want, need and if it will work. It should do though.