For those who Have Trouble loading Custom NSMBW Tilesets via Riivolution (A black screen appears when going to the level that has the custom tileset), here's a fix for you. I posted this on the wiki due to The Thread's XML on how to load custom tilesets was garbled up due to Blargboard.
Right-Click on your PC's desktop and click "New Text Document" and double-click on it.
Add these lines here in the file:
<wiidisc version="1" shiftfiles="true">
<id game="SMN"/>
<options>
<section name="Testing">
<option name="/NSMB Replacement">
<choice name="Enabled">
<patch id="nsmbfolder"/>
</choice>
</option>
</section>
</options>
<patch id="nsmbfolder">
<folder external="/nsmb" recursive="false"/>
<folder external="/nsmb" disc="/"/>
<folder external="/nsmb/Stage/" disc="/Stage/" create="true"/>
<folder external="/nsmb/Stage/Texture/" disc="/Stage/Texture/" create="true"/>
</patch>
</wiidisc>
Hit Save As in MS Notepad. Choose the Encoding as ANSI and change the file extension to .xml
All credit goes to Mario64 in the RVLution Forums. I do not hold any credit for the XML. Enjoy putting Custom Tilesets in your NSMBW Level. :)