Cant download a macOS installer- get error 30

I have a 6,1 on Monterey. I downloaded OCLP 1.3.0

I select to Create macOS installer, and select Sonoma 14.3 (but i9t does this with earlier versions too- i tried.)

I get an error after clicking Download, “ERROR Download failed: [Errno 30] Read-only file system:….” with folder information afterwards that I want sure was safe to post.

I’m guessing theres a setting in my end causing this.

Any help appreciated.