When you try to upload an image an click the "Send to server"-button, the upload animation will run forever and then timeout.
The trick is to do this:
From another post i understood that the trick is this:
everybody , Actually seemed to i have resolved the problem by
add code as below to the "editors\fckeditor\editor\filemanager\connectors\aspx\upload.aspx"
<head runat="server">
<title></title>
</head>