You did not answer the question directly I asked. Does that specific cat exist under the data directory
The problem with your Photopost application is you created a test category and then moved your photopost to a new server and the data directory you transfered did not exist. Once I deleted all those test directory and recreated a test now that the path was right things where fine.
You need to check in global options the data server path is right. Then delete any test cats in edit cats. You can then create a new cat and do an upload test
Please fully explain your issue you think you have next as all I got out of your post was its similar it is a ownership issue but no talk of what the problem is.