There is NO problem on your side.
There is nothing to fix on your part.
The problem is that somebody, somewhere on the planet, is abusing your e-mail address as the author of some SPAM campain. Also, he don't use his own computer to do that, but relies on 1000's of virus infected computers enroled in a bot-net.
Never EVER click ANYTHING you may find in any SPAM message, just delete the shit.
Ask your correspondents to do the same, and spread the word.
Never EVER post your e-mail address ANYWHERE, or obfuscate it in some way or another if you realy want to post it.
Use "AT", "à" or "À" after your user name.
Replace any "." by "DOT".
Replace any "-" by "DASH".
Add "REMOVE" or "NOSPAM" or "NO SPAM" anywhere in the address.
Put your domain name in a separate location than your user name.
Electro, May 2011