We have one issue in one of our installation: after selecting the files to be uploaded in the "Browse" dialog, we get the "FLM error:12030," (it seems I don't have permissions to upload screenshot together with this post, but I can send it to you by e-mail if you want it). Actually they've experienced a few different errors not only 12030. No visible errors in the Event log in the server.
As we can see on the screenshot, the upload is not even starting and no files are copied to the Temp folder.
Tested with IE9, Chrome and FF on Mac.
We are using windows authentication, and IIS is 7.5 on Windows 2008 R2.
Important: it works fine when used internally in the network. The problem occurs only when the web application is accessed from outside.
We had AjaxUploader version 3.0 20101019 installed, and recently upgraded to 3.0 20120112 in order to solve another issue, but the problem is still here.