I tried to load both the .bin and the .cue, but there's no difference.
I tried a lot of settings; with some of them (e.g., OpenGL plugin with only Framelimiter option enabled) I could enter the memory card manager, but with most of them the emulator freezed even while booting the bios only. There was one configuration (unfortunately, I don't know which one anymore) I had the best results with: while loading the game I could get past the "diamond" screen and the emulation freezed on the black screen with the PSX logo.
Strangely enough, if I tick "Fast boot" the emulator shows me the diamond screen all the same.
Thanks for helping