I have seen this error while opening a CHM file. After a little bit of struggling, I figured out that this error comes when you have this CHM file on a network drive and you try to open it from there.
The workaround for this problem is to copy the file to local drive and open it. I am not sure why having it in network drive is a problem. One guess I can make is, it is something to do with internet/intranet zones in IE w.r.t the network location from where you are accessing.
Have you followed any other to resolve this? Please let me know.
Also works if You you press ublock button in file properties.