It doesn't seem as though the template for exception emails is being found.

...
Caused by: sgf.gateway.mail.MailException: java.io.FileNotFoundException: Template unhandledexception/unhandled-exception-subject.ftl not found.
        at sgf.gateway.mail.impl.FreeMarkerMailMessage.processTemplate(FreeMarkerMailMessage.java:209)
        at sgf.gateway.mail.impl.FreeMarkerMailMessage.getSubject(FreeMarkerMailMessage.java:172)
        at sgf.gateway.mail.impl.FreeMarkerCommonMailMessage.getSubject(FreeMarkerCommonMailMessage.java:41)
        at sgf.gateway.mail.impl.FreeMarkerMailMessage.createMimeMessage(FreeMarkerMailMessage.java:102)
        at sgf.gateway.mail.impl.SpringJavaMailSender$1.prepare(SpringJavaMailSender.java:48)
        at org.springframework.mail.javamail.JavaMailSenderImpl.send(JavaMailSenderImpl.java:352)
        ... 75 more
Caused by: java.io.FileNotFoundException: Template unhandledexception/unhandled-exception-subject.ftl not found.
        at freemarker.template.Configuration.getTemplate(Configuration.java:489)
        at freemarker.template.Configuration.getTemplate(Configuration.java:452)
        at sgf.gateway.mail.impl.FreeMarkerMailMessage.processTemplate(FreeMarkerMailMessage.java:203)
        ... 80 more