I've ran into this issue too. Deleting the file that was currently being played is something even Winamp was too dumb to do right. But it at least told you when it failed and had a work around, by simply increasing the MP3 buffer to the point where the entire file would be loaded at once, and then it wasn't "locked" anymore and free to be deleted. Sadly is not smarter in the approach nor does it even tell you that it failed. And so far I've not found a way to tell it to buffer the entire file at...
Ancient reply and you probably figured it out yourself by now but the closest to...
Connection issues with 000Webhost