Thank you for the question, and I am very sorry about the issue!
I'm wondering if you import the climate file into a brand new file, does it work on that file?
There can be a couple of reasons why the climate file can't be opened by Archicad. Since the data is visible as shown in the screenshot, I believe the issue may not come from Archicad. I will forward the information to the Technical Support team for further investigation. In the meantime, could you share with us the climate file you are using?