Unfortunately, I'm not good enough to figure out how to properly fix this, I know in part where the problem itself comes from; In addition to using a strange format for their mouse pointer images the games in question also usually claim that the mouse pointer isn't actually visible.
In the meantime, however, I can offer a workaround. Quite some time ago, I made a modified game capture DLL for a friend of mine, since the mouse pointer in the new King's Bounty games didn't show up. I decided to take some time to implement this properly as a setting, and made new 32-bit and 64-bit DLLs, available here:
http://www.apehead.se/GraphicsCapture_ForceCursor_32.zip
http://www.apehead.se/GraphicsCapture_ForceCursor_64.zip
You can replace your GraphicsCapture.dll with those to get the option to force the default mouse cursor. There's no localized UI string for it, sorry about that. Also, OBS will tell you there's an updated version of Game Capture available, since it differs from the one in the updater database, but it's based on exactly the same code as the most recent one, merely with the addition of the new option.