Call to undefined function _simplenews_template_message() in ...... /sinplenews_template.modul on line 183

Hi!

If i wrote a message over the contact form i received this error

"Fatal error: Call to undefined function _simplenews_template_message() in /var/www/pomberger/htdocs/pomberger/sites/all/modules/simplenews_template/simplenews_template.module on line 183"

Do anyone have a solution for this?

Thanks for your help.