XSLT write   [resolved]

[blindlizard]

I am such an XML XSL noob. I am trying to write out & nbsp; (no space between the & and n, but the board keeps making it a real blank space) when an element named value is empty. I am doing it like this,

<xsl:when test="string-length(value)=0">
     &nbsp;
</xsl:when> 

but I get an error saying "Reference to undefined entity 'nbsp'"