When I try to upload new version of file it gets error - upload failure. It only happens with one file and with all browsers. (Chrome, Firefox, Opera, IE). I try to upload by admin but same error.
Could you provide some additional information please? What the file type is? What it's size/contents are? What the error message is/if there are any errors or stacktraces in the logs? You've said you're uploading a new version - so presumably the previous version uploaded ok and was of the same type, etc? Which version of the uploader you're using - Flash or standard HTML (if you know)?