Error with Upload Applet "can find no protocol"

Hello,
On my site when user tries to use "Upload Applet" they get pop-up message saying "Unkown Host"

Then i get following error

"Gallery Remote can find no protocol implementation at URL ....."
"Check with a web browser that ........ is a valid Gallery URL"

My URL is valid and so i am not sure what is wrong.

Can you please help to get this problem resolve????

BTW i do have "Remote" plugin version 1.0.17 activated
and "Upload Applet" plugin version 1.0.10 is activated

===================

I also observed below error on the event log;

Error (ERROR_BAD_PARAMETER)in modules\core\DownloadItem.inc at line 65 (GalleryCoreApi::error)
in main.php at line 450 (DownloadItemView::renderImmediate)
in main.php at line 104
in main.php at line 88

Request variables: Array
(
[view] => core.DownloadItem
)

===================

Regards,
Goopchoop