Problems on uploading app

Hello, this is first time I'm trying to upload an app, and I have some problems, mostly on upload proccess.
I'm trying to upload the apk file, which is 2Mb and doesn't seems to work. When I press the upload button the progressbar appears and after some minutes goes to 100% but nothing change and the filename doesn't appears(I suppose this must be happen). When I press again the upload button appears the message: an error occur, try to upload again.
Also I cannot upload any image. Pressing the relative button for screeshots appears a busy icon on the right of the button for a wild and then nothing again. The pictures are 640x384 and less than 500kb each. I've tried to make them smaller or change them from png to jpg, but again always the same thing happens.
And same behaviour for the icon.

Seems that the above are Firefox' s problem. Using Internet Explorer, all files uploaded without problems.

RE: Problems on uploading an app

Can you tell us the version number of Firefox you were using that failed to upload, so we can look at addressing an issue if there is one. Generally speaking, we have found the upload form to be compatible with IE, Chrome, Firefox, and Opera.