while i think i do have silverlight installed in my development environment, it is not something we use explicitly. but, having it there does allow ajax uploader to use it, i guess.
until you fix it, i may be best to switch to the flash method. ( iframe is just not acceptable )
my understanding is that UploadType="Flash" will force the uploader to use flash to transfer files, but i seem to loose the ability to select multiple files in the file browser. any ideas on why that is?
al