You can run Zorro S many times from the same folder, so you need not install different folders on the VPS.

As to the insufficient margin with Z5, be careful to keep enough capital on the account. Grid traders have a high margin requirement due to the many open trades. You can easily have a lot of equity on the account, but the available margin is zero and you cannot open new trades.

You should better not close trades manually. Let Zorro do that. It Zorro cannot close it due to no tradable price, you can't manually close it either, but Zorro will repeat the close command until the broker accepts it.