Hey bud,
I believe I fixed so that you'll be able to see the actual error now when you try to upload. Please let me know if it is still stopping you.
Don't worry about it, but I temporarily downvoted the non-flash Gemini presets due to them not at all generating the translated text properly when testing with paragraphs. Not sure if the models are flawed or if the prompt is. Also, I can personally not make any requests to the Pro versions, as it says that I hit the limit, so I presume they have no free requests at all.
Thank you for putting in effort into this. I'm going to upload some more presets to the LLAMA repository tomorrow, might hit a few Custom API ones too. :)