as mentioned here:
http://ww.wp.xz.cn/support/topic/has-failed-to-upload-due-to-an-error-the-uploaded-file-was-only-partially-upload
the problem is maybe on the server configuration. I just experienced that my test-server has no problem, if I turn of KeepAlive on the apache server.
Maybe this helps in your case as well?
I had the same problem here and unfortunately the problem is not fixed :-/
I already checked for a “query_post()” but still get no hits.. I have a test-server if you like to have a glance! I would appreciate it!
contact[aaat]ndsign-dot-ch