FOP bug: the index is not clickable

It seems that the index is not clickable because of a FOP bug.
Will there be a new improved FOP coming out, soon?

[ERROR] Unknown enumerated value for property 'span': inherit
[ERROR] Error in span property value 'inherit': 
               org.apache.fop.fo.expr.PropertyException: No conversion defined

See also
http://lists.oasis-open.org/archives/docbook-apps/200409/msg00056.html
http://lists.oasis-open.org/archives/docbook-apps/200507/msg00249.html

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EL6: Euis Luhuanam