Problem uploading files - Wikidot Community

I was trying to upload a file to my site http://sgovindarajan.wikidot.com/2009ph350assignments earlier today. I find that even though the uploaded file is rather small (40KB) but the upload does not even get started. I have tried this on Windows (with Google Chrome) and Mac OS (with Firefox) and both of them fail. Clearly, this is something I have done several times, the last time was a couple of days back and everything worked.

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