https://i.imgur.com/K4eY7JL.png
This happened when I pressed Ctrl+Tab, I've tried changing the controls but the same thing happened.

Exactly what I did:
1. Install the mod
2. Make a new sandbox world
3. Try to switch weapons
4. Read the error

All the other mods I had installed:
- Asphalt Roads
- Base mod
- Extended Vanilla: Exoskeletons
- Extended Vanilla: Fusion Reactors
- Extended Vanilla: Personal Roboports
- Extended Vanilla: Power Armors
- Inserters with eyes
- Pushbutton
- Quality of Life research
- Renai Transportation
- Robot256's Library
- Santa's Nixie Tube Display
- Spidertron: Deal With It Sunglasses
- Vehicle Wagon 2
- YIR - Americans
- YIR - Uranium Power trains
- YIR - Yuoki-Industries-Railroads
- Yuoki Industries - Railways

Thanks for the report. The issue was it that it crashed whenever the player had no associated character because the inventory is accessed differently. Fixed in 1.1.2.