This issue happened more than 10 years ago.
I have a .Net app that calls visualcron that is not currently working with the dlls of VC 9 on 64 bit.
But it does work great on 32 bit.

My .Net app is already on .Net Framework 4.8 and if using 32 bit everything works fine.

So my assumption is that the visualcron.dll and visualcronAPI.dll are not 64 bit compatible.
Note: It also doesn't work if I use