You are trying to renew/request a SSL certificate and need to generate the CSR (Certificate Signing Request). You press the Request button, enter your password but get the error "Invalid Keyfile Accessed".
This is caused by the path in the top field being incorrect.
F:/Lotus/Domino/Data/mykeyfilename.kyr (which is where it really is)
Fix the path. Hit F9 and press the button again.