It should be working now. Turns out IIS7 has a hidden 30MB upload limit, so I've bumped it up to 200MB. Once set I was able to upload a 300 dpi scan of Mega Man X6 which weighed in at 47MB.
Thanks for the heads up, I'll see what I can do.
You should be able to update your own manuals, though I haven't tested that in ages. I'll see if I can figure out what's wrong.
As for your upload timing out, it's currently (supposed to be) configured to timeout after four hours with a max of 200MB per manual. Are you on broadband? Does it seem to cut off after a specific amount of time? This is really difficult for me to test so any info would be extremely helpful.