I'm getting errors during build in my Flutter project

Hello, I am getting 'No such module ''Flutter'' and ''Couldn't update repository submodules'' errors during build in my Flutter project. I want to make System Navigation Bar and Status Bar transparent, I tried many commands, I can change color, I can hide it but I can't make it suitable for transparent background. I'm new to Flutter and I'd appreciate it if you could help. I am using Mac in virtual machine, you can connect with Chrome remote assistance.