What happening with this .mpe file?

Factual Questions
1

I received a an email attachment of a video file that was encoded with an .mpe file extension. I opened it and it played normally in Irfanview, but when I went to save it to disk, ‘save’ and ‘save as’ are disabled. If I try to save the attachment from Outlook, I got an error message saying “Outlook cannot save the URL to file. Can’t find this file. Make sure the path and file name are correct”. The file is 986k, so it is more than just an URL that links to a file on the web. The other odd thing is the original email attachment file has the extension .mpe, but when I open it with Irfanview, the extension is .mpc .

What is going on with this .mpe file, and should I be worried about its source?

2

I’d try renaming the file to the .mpg file extension and see if that doesn’t clear up the problem.