I never succeeded in getting the OLED example code to work, either on the 168 (by removing the variables as suggested) or unaltered on a 328.
I think I can confirm the display is not busted, though, because I was able to send it basic commands using a Bus Pirate. I’m trying to debug the most basic of I2C interfaces using the Seeeduino as the controller, even with the same simple commands that I used on the BP, I cannot get it to show anything (or even come on). I’ll double-check the power, too, that might not be working for some reason.