I was under the impression that this worked with acorn.tv, but I'm not able to record anything from acorn.tv. Please help.

You have two methods you can capture with AUTO mode or DVR.  As it's a premium content site you will probably need to use the DVR mode.

https://www.jaksta.com/support/windows/kb/user-guide-jaksta-media-recorder-for-windows-v6-6000039105#guide-digital-video-recorder

If your having issues please provide debug logs as per  https://support.jaksta.com/discussions/topics/6000009063