The text to speech plug-in specified {0} is not a text to speech plug-in.
A text to speech plug-in must extend com.ibm.telephony.directtalk.TTSPlayPlugIn or TTSGeneratePlugIn. The class specified is not a text to speech plug-in. This error is not reported if the wrong TTS plug-in type has been specified in the configuration.
Ensure that the correct class is specified in the configuration and that the correct version is accessible via CLASSPATH.