xslt-problem: maximum length of xpath-expressions?

hi,

i've got the following problem:

i'm using xsl:sort within a xsl:apply-template expression.
the select-statement contains a quite long xpath-expression (around 
1800 characters including cr/lf).

applying the stylesheet on my xml-document using xalan2 i get the 
following error message in response:

javax.xml.transform.TransformerConfigurationException: 
javax.xml.transform.TransformerException: 
java.lang.ArrayIndexOutOfBoundsException

if i shorten the select-string at any reasonable position so that the 
whole xpath-expression syntactically still makes sense, the 
stylesheet is processed just fine.

is there any known limitation on the allowed length of xpath-
expressions?
did anybody have a similar problem so far?

any hint is appreciated.
cheers,
frank.