WHMCS MU Provisioning Causing Media to Not Upload

I'm having an issue with a site on my multisite install. I've never seen this before, but WP is not uploading media to the blogs.dir folder. However, it's working for all remaining sites on the network. The only one it isn't working on is the one that was created by this plugin.

I've tried creating new sites manually and they work fine. I've also tried creating a new site using the provisioning plugin and the new site is behaving in exactly the same way - not uploading the media files.

I've attached a screenshot of what the media uploader shows after I've uploaded a file. I've tried both the single file and multi file uploader. Notice how the thumbnail of the image isn't showing. I've gone through the settings on each of the sites and everything appears to be correct.

Any thoughts? Can you help me with troubleshooting further? Thanks!