Hi,
IE modal dialog is a special case , it have many compatible issue.
I suggest you use an iframe for the dialog .
that means
window.showModalDialog("theiframepage.html")...
in the theiframepage.html ,
use <iframe src="myuploadpage.aspx"></iframe> to include the uploader.
I think all silverlight/flash upload component will meet the same issue.
If you have more solution rather than iframe , please let's know .
Thanks.
Regards,
Terry.