It’s really hard to debug on those mobile browsers. May be you can try changing the files and try to fix it and let us know. We’ll be glad to fix that too.

I’m not using any mobile browser, actually I’m testing in every major one (Chrome, Safari, Opera, Firefox and Internet Explorer), I fixed it myself.

in frontend-form.js where there is:
imageUploader.bind('Error', function(up, err) {
it must be
imageUploader.bind('Error', function(up, error) {
and it’s missing this line to remove the progress bar
$('#' + container).find('#' + error.file.id).remove();

With this everything works as it should, I’ll make more modifications to implement jquery alert boxes instead of the javascript default ones, so any future update will be fully checked for compatibility with my ‘version’.

Thanks for all the help.