Blackberry phone help!?

So quite recently, whenever I try to download any kind of files from a website onto my memory card it tells me "Unsupported media type: application/octet-stream" I have no idea what this means & why all of a sudden it's saying that when it was working perfectly fine & letting me download files before ?? Btw I have a Blackberry Bold 9780, I was looking up some other answers & people were saying something about "browser configuration" but that's not under my browser options so help! Please if you can...