Try to use /usr/bin/test or /bin/test to work around missing features.
The builtin "test" of Solaris 8 /bin/sh doesn't understand -nt.
<item>
<title>#desc|strip|firstline|strip|escape#</title>
<link>#url#?cs=#node|short#</link>
<description><![CDATA[#desc|strip|escape|addbreaks#]]></description>
<author>#author|obfuscate#</author>
<pubDate>#date|rfc822date#</pubDate>
</item>