Look for this page to get improved in the future...
Problem:
Can not convert #STRING to a NodeList!
Clues:
one problem is that you have a string comparison with single quotes around it.
another problem can generate the same error if
<xsl:for-each select="$currentNode/node">
and the variable $currentNode is null. this becomes some sort of string and cannot be evaluated as a node set.
Data To Use In Examples
<data>
<garage id="1"
>
<level id="1"
>
<car id="someid3222223"
>
<entry-time>
</entry-time>
<make>
Ford
</make>
<model>
F150
</model>
<year>
</year>
</car>
<car id="someid32333"
>
<entry-time>
</entry-time>
<make>
</make>
<model>
</model>
<year>
</year>
</car>
</level>
<level id="2"
>
<car id="someid322323"
>
<entry-time>
</entry-time>
<make>
</make>
<model>
</model>
<year>
</year>
</car>
</level>
<level id="3"
>
</level>
</garage>
<garage id="2"
>
<level id="1"
>
</level>
<level id="2"
>
</level>
<level id="3"
>
<car id="someid322323"
>
<entry-time>
</entry-time>
<make>
</make>
<model>
</model>
<year>
</year>
</car>
</level>
</garage>
</data>