How to Convert .GBS file (with .m3u addresses) to MP3 using Winamp? [Error]

[Areaxis]

Hello, I've recently downloaded an audio directory from zophar.net and I've been able to play .gbs file music w/ m3u's included using the Winamp "Chipamp" plug-in. However, when I try to convert those files into mp3 from the playlist menu, I get an error "Cannot find decoder" every time I try to do it.

I found a forum thread in another website regarding the same problem where the troubled individual was able to find a solution by "selecting every file from the playlist and then converting" here is the link to that thread: http://forums.shoutcast.com/showthread.php?t=291403, which I tried but alas didn't work either. I'm sorry if the description to my troubleshoot is a little vague, but thats as far as I could speculate on the matter. Alternatively, I've been thinking about directly recording the audio from winamp using Audacity, but until then I would like to have a solution to this since its less of a hassle.

Any help would be appreciated, thank you in advance. 

[Jorpho]

However, when I try to convert those files into mp3 from the playlist menu

I wasn't aware that was a thing you could do. Isn't the standard way to use the Disk Writer output plugin to convert to WAV?