Hello,
Unfortunately I don’t think Box supports PHP at the moment. It may be possible to use another API to handle the upload request that’s sent by PennController, but I never got around to trying that out because I only have access to Box through a university account, and administrators won’t grant access to the API for security reasons. If you are also using Box via an institution, I encourage you to inquire about it before spending too much time and energy on this. I can see why you’d rather not add another third party in the loop for data collection, but I have to say that using Dreamhost would definitely be much easier
Let me know which route you end up deciding to go, I would be happy to provide assistance either way
Jeremy