I have also recently experienced the, Unexpected token prompt, followed by error 999, when trying to upload files. I contacted my provider and was given the following message (please note I am not nearly as technically savvy as the moderators or the original poster, so I have no idea what the provider is trying to say.).
Hello,
Thank you for contacting HostGator. I’m sorry to hear that you’ve been experiencing problems with your upload functionality provided by the ‘simple-press’ plugin. I’ve investigated the issue and found that the files actually do get uploaded successfully, but there is a coding issue with the plugin which triggers the ‘Unexpected token <‘ error.
I ran a stack trace against the PHP process while uploading a file and found it was uploaded, then moved successfully:
09:27:31 open(“/problem-with-post-edit-buttonome3/advocate/public_html/wp-content/sp-resources/forum-file-uploads/johndurham/2014/07/”, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC) = 5
09:27:31 getdents(5, /* 7 entries */, 32768) = 224
09:27:31 rename(“/problem-with-post-edit-buttonome3/advocate/public_html/wp-content/sp-resources/forum-file-uploads/johndurham/2014/07/testfile-2.txt_”, “/problem-with-post-edit-buttonome3/advocate/public_html/wp-content/sp-resources/forum-file-uploads/johndurham/2014/07/testfile-2.txt”) = 0
Shortly after that, it writes out a success message:
09:27:31 write(1, “{“jsonrpc” : “2.0”, “error” : {“code”: “0”, “message”: “File successfully uploaded”}, “type” : “file”, “file” : “testfile-2.txt”, “size” : “13”, “width” : “”, “height” : “”}”, 173) = 173
However, the ‘unexpected token’ error is making the upload form believe that the file did not get successfully uploaded. You’ll need to get in touch with the developer of this plugin for an update, or a fix to the coding issue. Please let us know if you have any further questions or issues and we’ll be happy to assist.
I hope this information is helpful. I look forward to your assistance.