dTunes and Safari DL Plugin Troubles

So, recently I've been having problems with dTunes not showing new videos I download from MobileTheater. It's on an iPod Touch 4th gen, with JB 4.3.1 firmware. As well, it seems like the Safari DL Plugin is very hit-and-miss in terms of actually downloading a file from MegaUpload. Sometimes when you click Download, it just brings up the Can't Play logo you get while browsing and there's an embedded video, or sometimes it says the file I try to download is 70 something KB large, and it flat out won't work.

Is this just the result of files being too old and not compatible with the programs anymore, or is it something I can fix?