What kind language resouces you use?
I checked and found misstake in resouces, right now.
(some mail_template file are lose)

Please put on language/XXX/mail_template/notify.tpl in your language XXX. Other files compare from language/english/mail_template/*.tpl

notify.tpl as followed:
=======
Hello {X_UNAME},

A new event "{EVENT_TITLE}" has been added at {X_SITENAME}.

Date: {EVENT_DATE}
Title: {EVENT_TITLE}
{EVENT_URL}

{EVENT_NOTE}

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You are receiving this message because you selected to be notified when new stories are added to our site.

If this is an error or you wish not to receive further such notifications, please update your subscriptions by visiting the link below:
{X_UNSUBSCRIBE_URL}

Please do not reply to this message.

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{X_SITENAME} ({X_SITEURL})
webmaster
{X_ADMINMAIL}
=======
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安冨　伸浩 (マイサイト管理人)