No, the Position Sizer trades on its own, without the PSC-Trader script. The "Trade is disabled" error can appear in the following cases:
- Autotrading is disabled in the platform.
- Autotrading is disabled for this EA.
- Trading is disabled for your account.
- Trading with EAs/scripts is disabled for your account.
- Trading is disabled for this specific currency pair (symbol).
- Trading with EAs/scripts is disabled for this specific currency pair (symbol).
In the first two cases, you can just enable autotrading yourself. The latter four require understand what's going on with your broker. Some brokers reserve some symbols for charting only and offer different ones for trading. Some brokers also offer separate symbols for autotrading.