Strange error using pubflatFileconvertToString

Hello All,

I’m facing this error when I try to use convertToString service: “java.lang.reflect.InvocationTargetException:com.wm.ff.parse.Converter.cvtToString(Lcom/wm/data/IData;Lcom/wm/ff/parse/interfaces$NodeUsageContainer;Lcom/wm/ff/parse/interfaces$RecordIdentifier;Lcom/wm/ff/parse/interfaces$RecordParser;Ljava/io/Writer;[CZLcom/wm/ff/parse/NodeUsage;Ljava/lang/String;Lcom/wm/data/IData;ZZ)V”

This error begins when I upgraded the IS 6.1 to IS 6.1 SP1.
This error happens in a production environment but in development, with the same configuration, it never happened.

Anyone have faced this problem before?