XFileSharing Pro - File server upload issue

[Desita]

I'm having an issue when attempting to do a standard upload to any additional file servers.

My browser is registering an error 500 because of:

"No 'Access-Control-Allow-Origin' header is present on the requested resource."

I checked the upload.cgi file but it does have:
print("Access-Control-Allow-Origin: *\n"); # Allow Cross-domain XHRs

Any idea what might be causing this error? It happens on both file servers.