First, WELCOME!
I know what that error is.. but I can't duplicate it.
So I'm selected on the NL server... I go to the upload test and select a size manually... it works. I run an automatic test and select the sizes manually.. it works. I run other test types.. they work... I run download tests... they work too.
I believe that you got the error... I'm just wondering why. That happens when form data required to process the results is missing from the request.
First, try again... this may have been tied somehow to a glitch earlier that I resolved. (although I doubt it) ... if i