What I'm getting from your post, is that you're having problems when using the SlingLinks
In this case, please note that the SlingLinks are just powerline bridges, working under the same electrical circuit. To discard them as a potential issue, I would recommend to try a different wall outlet for the SlingLinks just to troubleshoot.
I've tried varying outlet combinations. The Slinglinks works just fine -- my issue is with the noise I get through my computer speaker system -- even when I'm not actively using the Slingbox. I have mitigated it slightly by trying those magnet thingies on the power cord to the speakers, but it is still slightly there. It's really just a minor irritation -- kind of like a small stone in your shoe -- it doesn't bother you too much, but you're constantly reminded it's there.