Ups!
Quality check was not very good last evening :-(

> In this case, the code marked with the asterix (*) will be:
> <!-- (Muenchian Method) -->
> <xsl:for-each select="$eventdate-by-month-and-day"
> use="concat(position(),'_',$pos)">
>  <br/>Time: <xsl:value-of select="@time"/>
>  <br/>Event: <xsl:value-of select="event"/>
> </xsl:for-each>

Completely wrong syntax in the for-each (copy-paste error)
With the same key, the for-each should be:
<xsl:for-each
select="key('eventdate-by-month-and-day',concat(position(),'_',$pos))>

With this change, the stylesheet should work.

Regards,
Ragulf Pickaxe :-)