ERROR IN JAVA PROXIE WHEN INVOKED METHOD

Hi all, we have the follow problem:

JPR could not process the message. Reason: Error invoking method mIPOMLPIN of proxy bean $Proxy192: java.lang.StringBuffer.append(Ljava/lang/String;)Ljava/lang/AbstractStringBuilder;

The asynchronous message was successfully scheduled to be delivered at Fri Nov 11 21:31:37 GMT 2005.

Delivery of the message to the application using connection JPR failed, due to: Error invoking method mIPOMLPIN of proxy bean $Proxy192: java.lang.StringBuffer.append(Ljava/lang/String;)Ljava/lang/AbstractStringBuilder;.

anybody could help me pleas to undesstad this ??