Check out this thread for more info: what does it mean if the file is corrupted?

Also, try another search for the same files. Find a single modem source & download the file from them. Is that any different?

Don't forget to check files with Bitzi before download.
How to use Bitzi
Even though audio files aren't often rated, if the files are crappy then there might be some info about them.

When LW detects a corruption, it doesn't necessarily mean that the file's infected, or even that it's unplayable. But there are lots of infected files on the network! So you need to make sure that you're using a good AV program. Keep it updated & use it to scan every file that you download - before you open the file

Virus thread: Typical virus spam file sizes - Make a note of them (click on blue link to see)

* WARNING: Viruses on network you should be aware of ! *