You do have winamp right? The file Swedix gave u should work, I just used it and i works fine. Have u read the readme file?
taken from the readme file:
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It doesn't work!
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Happens. Please read through this hints before complaining...
1. Does the plugin show up in the Preferences window (Plugins, Input)? If it doesn't, go to your Winamp's plugin directory. Is in_umx.dll there? If not, reinstall the plugin, this time into the correct folder...
Is in_mod.dll there? If not, reinstall Winamp. Also note that the MOD plugin is missing from Winamp Lite. You need at least WA Standard.
2. UMX files don't have the Winamp icon in Explorer etc. - Check Setup, File Types in the Pref window. Is "UMX" selected in the listbox?
3. Certain UMX files don't play correctly.
Please try playing them with UnrealEd (Unreal Editor) which is the normative reference concerning UMX. Also try exporting them to disk (as .MOD / .IT file) to try if Winamp's MOD support is the problem. If any of those fails, it's a problem with your hardware, drivers, or setup.
4. The latest version of the plugin is available from
http://www.rootshell.be/~ptr2void/umx/
Does that help?
Also make sure you installed teh decoder into the winamp directory.