Here's a problem that often occurs when writting text with lists here (may be after copy/paste, I'm not sure): at the end of the line no more text can be added.
Try to add text after the last letter of "FF, F". The <br><br type="_moz"> seems to prevent any text to be added.
<ul> <li>Update to 1.4.1, clear cache, the problems remains.</li> <li>Two plugins (not extensions) are enabled: shockwave flash 184.108.40.206 & shockwave flash 11.8.800.168. It seems the new update didn't uninstall the former one<br> => Disable one of them, the upload can only start in single file upload (black overlay uploader) <br></li> => Rename C:\Windows\System32\Macromed\Flash\NPSWF32_11_8_800_168.dll to disable it in FF, F<br><br type="_moz"><li>Adding SWFObject fixes the problem in every case</li> </ul>