IDPosteriorErrorProbability crashes

Hi,
I use IDPosteriorErrorProbability after OMSSA but it crashes with the next message:

terminate called after throwing an instance of ‘boost::exception_detail::clone_impl<boost::exception_detail::error_info_injectorstd::domain_error >’
what(): Error in function boost::math::normal_distribution::normal_distribution: Scale parameter is -nan, but must be > 0 !
Aborted (core dumped)

As I understand the tool didn’t manage to obtain the scale parameter, but why can this be ? Is there anything to be done to avoide thes problem ?