I think I am  quite clear now. SO I can think that As
I am inside for loop of RTF so key selects nodes in
RTF which does not produce any result.

Taking a more close look at what you mailed earlier, I noticed the definition of xsl:key. Though, 
the definition of $levelreference is missing, but I assume that is a reference to a document fragment.



Yes, the problem in your case is that you switch context from input doc to fragment with your outer 
for-each loop. Doing so makes the key work on the fragment instead of the input doc. Your lines 
above are on the right track...



I assume that the key you specified is supposed to work on the input doc rather than the fragment. 
Well, you could use the following trick to switch back context to the input doc:



<xsl:variable name="current" select="." />



<!-- outer loop -->
<xsl:for-each select="node-set($levelreference)/*">
  <xsl:variable name="id"  select="@levelref" />

  <!-- here comes the trick :P -->
  <xsl:for-each select="$current">

    <!-- compressed inner loop to one value-of statement -->
    <xsl:value-of select="key('professionlevelkey', $id)/@value" />

  </xsl:for-each>



</xsl:for-each>



But again, if you can tell us how you construct $levelreference, we might be able to suggest an even 
better solution, preventing use of fragments at all perhaps...



Cheers