Can't edit topics offline

I Work From Home (WFH) a couple times a week and am working in RH with one other writer and we are tracking our changes in SC. Since the network is really slow, I thought I could work on the topics offline and then check them in when I go into the office, however, whenever i make a change to a topic, I get an error box like this:

I can't make any changes to any topics or snippets, and I've checked my rights as a SC user -- I have all rights. I've also tried checking out files but no can do. I thought I was able to do this offline when WFH. Is there another setting I'm missing? I've looked in the Help and there's not much about working with topics offline, so I'm really not sure what my restrictions are.