jbear, let me comment. I've been lurking here for a couple of years with nary a problem. OK, I lost my password a couple times but that was my own fault. Here is what I think OK?
I get stuff on my firewall all the time, but I stopped it from both sending and receiving. It auto-updates based on some pretty strict rules regardless of where anything comes from. I have to actually click on or enable anything manually before it happens. I'm on a cable modem but DSL is similar; anybody on the service could be sending stuff whether they know it or not. Sometimes somebody puts a bum download without even knowing it -- I didn't have any problems. You might want to delete the first one and try again just in case.
I use linux, which is very similar to Apple Mac OSX, but Windows has things all its own. I can't afford a Mac so I had to learn... I would do a good cleaning on my machine to get rid of any possible spyware and viruses. Use a few different products for it because they don't catch everything. Yeah, I know it takes a while, I've done it. Make sure you have a decent firewall setup; even one of the little Linksys or D-Link routers should do it, usually for less than $80 bucks. Keep it all up to date with the latest fixes; windows does it auto-magically at midnight or something like that. You paid for it, so use it!
Sometimes it also happens that somebody sends a bum zip file or has a slightly different zip version. Ask them about that. Or their site might have a problem, but I'm sure this site doesn't for a fact.
Yeah I know its a lot because I did it years ago, but I hope this helps somehow.
-Take care out there on the 'net