osg-configure has the following 4 exception classes:
Despite the description, ConfigurationError is not the base class for the other exceptions – and is not used anywhere
ApplicationError is not used, except as a superclass for ConfigureError
Sometimes invalid options raise a SettingError, sometimes they raise a ConfigureError – it seems to be inconsistent
ConfigurationError and ConfigureError have names that are too similar
Also, make sure that none of the above are considered an "Unknown exception" in the logs.