I've had this issue too, and I tried contacting LimeWire tech support to get an answer from them. I have to admit that I am not the most computer savvy person in the world, but I manage to navigate my way through most of the time without trouble. I made the mistake of referring to LimeWire as a music download tool and was told very specifically (and non too nicely I might add) that isn't what LimeWire is.
To get to the point, I find it interesting that some people have relied to this thread saying that when they upgraded to the new version (and getting PRO costs you $18.88 all over again) the problem disappears. Yet the response I got from the rep said this:

LimeWire is not a "service" of any kind; it is filesharing software.
-We do not, and cannot, control what people decide to place on the
network, for other people to download.
-The problem is not because of some "glitch" in LimeWire; it is because
some people have decided to share questionable material over the network.
-If you still do not understand what I have explained to you, several
times, I strongly suggest reading the information that is available at our
website. There is really nothing else I can tell you, that I haven't already
told you. Making sugestions about a technology that you don't understand, will not help anyone.

I do understand that if the problem is in the file that I am choosing to download, it would still exist even if I upgraded to the new version because the file isn't connected to LimeWire "software". I think its interesting that the problem has gone away for the users who upgrade.