Hi Kenneth           Thank you so much.... It is working fine. With out silver light also it is working fine in other PC(Mozilla 3.6.4). But in my PC it's working after silver light upgradation only. May i know why this happened  as well as the relationship between Silverlight and Ajaxuploader and Mozilla ...

Im using the uploader in a <IFRAME> (not hidden tho, directly interacting with it), in firefox (3.6.3) and silverlight 3 >, I get a message saying I need to install silverlight. I have the latest build (3.0 20100414).