I'm not sure I understand the first part about identifying "what is causing this error", since you have already found the bug. But in case you haven't seen this note, it's a little more verbose than the Bugtool, specifically:
https://supportforums.cisco.com/docs/DOC-1660
"Resolution
If there is no adverse effect on the functionality of the PoE line cards, treat this message as an informational message only. In this case, no action is required.
As a workaround, try to reseat the affected line card first. If the error still persists, then please contact Cisco Technical Support online using the TAC Service Request Tool."
As far as how to "be alerted through email when this occured", if you have CiscoWorks LMS 3.x, this could be easily done through the Automated Action feature:
https://www.cisco.com/en/US/docs/net_mgmt/ciscoworks_resource_manager_essentials/4.1/user/guide/chgaud.html#wp1034685
It's a bit more convoluted in CiscoWorks LMS 2.x:
http://www.cisco.com/en/US/products/sw/cscowork/ps2073/products_tech_note09186a00800a7275.shtml#topic6
Without CiscoWorks LMS, one alternative is to use EEM (Embedded Event Manager) to generate the email, provided the IOS ( 12.2(20)EW? ) supports it. Here's an example in a recent thread:
https://supportforums.cisco.com/message/3047854
