I know virtually nothing..about viruses that is

My brother sent me an email saying he has received 2 emails from me with attachments on them, but I didn't send either one of them.  We both assume it's a virus, but we don't know what it is.

The attachment on the 2nd mail was this:

ATTACHMENT part 2 application/octet-stream name=the_message.scr

Anybody have any ideas?

Many viruses are able to spoof the address of someone else.  By that I mean, I might be infected by virus X.  X looks through my contacts list and pretends to be Raptor and sends itself to you.  You get an email that looks like it came from Raptor but it really came from me.

Other viruses can send themselves without showing in your sent list.  You might be infected but not know it.

Try scanning for viruses,

http://www.grisoft.com/us/us_dwnl_free.php - AVG Anti Virus - Freeware

or

http://housecall.trendmicro.com/ - Trend Micro - Free

I know very little about E-mail, but if the problem occurs more often you may have to contact who ever provided you with that E-mail adress.

A very simple precaution can be to get into the habit of using a meaningful title field, something that you and your respondent would know but a malware bot wouldn't.
"Your pics" doesn't mean anything, but "pics of Jule's wedding in May" does.

It's not foolproof but does make for a good habit with your email correspondees.

Excellent point Mark.