Recently I installed Minecraft 1.6.4 and tried afterward to install Forge 1.6.4. I tried different versions of the installer like:
9.11.0.898
9.11.0.897
9.11.0.884
But everytime I open it I get a window with "Mod system installer" for title, a "OK" button in the bottom right and nothing else.
I can't even click the button and can't close the window.
I tried updating my Java but it's up to date. I also tried looking for tutorials to help me install it in case it was a mistake from my side but nothing helped.
And just to mention if it can be helpful, my OS version is 10.6.8.