We seem to have the same problem with a Windows 8.1 x64-PC with version 18.104.22.168, too.
The communication works fine but the connection gets also lost after seconds up to minutes.
In the device manager the card is available without any errors, but neighter our C#-program nor the DEMO-program can connect to the K8061 anymore.
Unfortunately v22.214.171.124 doesn’t work with 8.1 anymore, it forces an exception.
Exists a patched version like v126.96.36.199 which doesn’t disconnect the card if an Commucation error occurs?
The DLL v188.8.131.52 is in the folder: …\K8061DemoVC#_2010\K8061Demo\bin\x86\Debug
There is also other required file mpusbapi.dll.
You can copy these DLLs to folder C:\Windows\SysWOW64.
The DLL v184.108.40.206 and the C# demo are 32-bit software.
I have tested this demo/driver combination on Windows 10 (64-bit). It should work on Windows 8.1 too.