Namely, change
Content-Type
to text/plain or
remove from the message body
Subject: $message
Mime-Version: 1.0
Content-Type: multipart/mixed;
boundary="----=_Part_3_25047450.1312994887640"
X-Antivirus: avast! (VPS 110810-0, 10.08.2011), Outbound message
X-Antivirus-Status: Clean
X-Spam: Not detected
X-Mras: Ok
------=_Part_3_25047450.1312994887640
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Message: $message
Device: $displayName
Category: $category
Error Condition: $stringseverity
Generated at: $strModTime
------=_Part_3_25047450.1312994887640--
part with