Keep Getting an Error on MP4 Upload

[jeff_harrington]

My Grand Tango for Solo Violin has got an optional video accompaniment. I've tried twice now to upload an MP4 files (I'd really prefer a MOV, but that's a different topic) and both times it threw an error on completion. It was, (sorry) an File Not Found error, I believe, basically a blank page with the error and not much else. I'll try again if you guys need me to send the error back, there just wasn't much info.

[jeff_harrington]

Just tried it again, here's the error:

Error
This page should be access via a link on a work page.

URL: http://imslp.org/index.php?title=Specia ... ion=submit