Character encoding not recognized in pages don't loaded in first place

[APuertaSales]

Hi all.
I'm trying to use pdf.js to serve PDFs from my WEB page. I've installed the code on my server and I've prepared a demo:

http://visionmedia.dev.cervantesvirtual.com/web/220816.html#page=15

It's a huge PDF, to test.
If you make scroll to a page up or a page down (sometimes 2 or 3 pages up or down), you find that the encoding changes and you can't read the text.
In the first page I don't get messages from my Firefox console, but when I change the page until I find one with the wrong encoding, I get messages in console:

downloadable font: table 'glyf': failed to parse table (font-family: "g_font_p23_6" style:normal weight:normal stretch:normal src index:0)
downloadable font: rejected by sanitizer (font-family: "g_font_p23_6" style:normal weight:normal stretch:normal src index:0)
downloadable font: font load failed (font-family: "g_font_p23_6" style:normal weight:normal stretch:normal src index:0)

But I don't have any of this errors if I try this PDF in Firefox opening it locally: I show the encoding fine in every page and I don't get any message in console.

Thank you in advance.

[APuertaSales]

Thank you very much.