unfortunately error 5 just says that a file could not be opened. In most cases the reason is an unspported codec. wav is just a container format like wma or mp3 - but it depends on what's inside of that container. You need the appropriate codec to be installed. Some codecs come with windows, some can be obtained for free and some require you to purchase a license.
You could try installing a codec pack like this one:
http://www.xpcodecpack.com/
Sun, 2010-10-03 20:27 | 
nologin (not verified)
Hi, unfortunately error 5
Hi,
unfortunately error 5 just says that a file could not be opened. In most cases the reason is an unspported codec. wav is just a container format like wma or mp3 - but it depends on what's inside of that container. You need the appropriate codec to be installed. Some codecs come with windows, some can be obtained for free and some require you to purchase a license.
You could try installing a codec pack like this one:
http://www.xpcodecpack.com/
I hope this helps,
Chris'