question about JTidy

Hi, i downloaded Java version of HTML Tidy Release 4 Aug 2000. After i
imported the source codes into JAVAVisualAge, an error detected in the
method "addProps(Properties)" in the "Configuration" class as follow:

_properties.setProperty(key, value);  "method not defined"

Would you pls let me know how to fix this problem? Thanks.

Liwen