I recently encountered the same problem. The reason is that a recent version of VESC Tool added firmware compression, new update mechanism.
VESC Tool thinks that Ackmaniac supports firmware compression (since firmware version is higher). But it does not.
Do the following:
- Get correct firmware bin file from https://github.com/vedderb/vesc_tool/tree/master/res/firmwares (matching your hardware)
- Use Ackmaniac ESC Tool to flash this bin file
- Afterwards you will be able to use VESC Tool