Starting with version 1.4.1 you can upload any file by using the "Link" button and then the tab upload (if you enabled this feature in your admin settings).
Unfortunately the filename gets changed -> the dot in front of the file-extension gets replaced by a minus.
xyz.doc will become xyz-doc
Is this a compatibility feature for HTTP headers and browsers or a bug?
To overcome this I modified the qa-blob.php in the line 66 (just added the \. ):
$filename=preg_replace('/[^A-Za-z\.0-9 _-]/', '-', $blob['filename']);
up to now I could not see any drawback... :)