Check what version of Ninja you are running - 32 or 64 bit. Click 'Control Center - Help - About', see Version.

For 32-bit NinjaTrader 8 install MZpack 32-bit version.

For 64-bit NinjaTrader 8 install MZpack 64-bit version.

We don't recommend using MZpack 32-bit version with 64-bit NinjaTrader 8 on 64-bit Windows.