Problem with WordExtractor

[WATHELET Thomas]

I try to extract some word document with this class:
org.apache.poi.hwpf.extractor.WordExtractor
 
I retrived this error message:
java.lang.StackOverflowError
 org.apache.poi.hwpf.model.StyleSheet.createChp(StyleSheet.java:265)
org.apache.poi.hwpf.model.StyleSheet.createChp(StyleSheet.java:266)
...
 
What's happends?