it looks like you might be using temp files to manage fixture files across requests. unfortunately you can't do this, since your request could get served by any number of workers which don't have access to each other's file systems. 

you are going to have to use something like redis to store this. the easiest way is likely to use the soil framework that we use in other places, like case importer and exports.

https://github.com/dimagi/commcare-hq/blob/master/corehq/apps/importer/views.py#L54 is an example from importer that can get you started.