Oracle XML parser not supporting tokenize?

With regard to my previous message, concerning the tokenize function:

I have attempted to use the tokenize function of the 
http://www.oracle.com/XSL/Transform/java namespace, but the output is 
only the XML declaration. No error, no table (which should be there 
anyway), no nothing.

The relevant code is:
<xsl:when 
test="ora:tokenize(mpp:ExtendedAttribute/mpp:FieldID[.=188743740]/following-sibling::mpp:Value, 
',') = ora:tokenize($keyword, ',')">

, i.e. continue when any of the comma-separated values equals any of the 
comma-separated keywords.

Can anyone tell me why this doesn't work?

-- 
Victor