Thank you for posting.
Looks like you are not getting an ACK because you are not sending the right address. Try sending 0 1 0 1 0 0 1 0 (0x52) .
You are capable of communicating at a maximum of 100Kbs.
The way to send data to the display is you send the address, then the command or text.
The LCD is always the slave.
The following link is a sample program of using I2C with the unit which can be helpful to you. http://www.lcdforums.com/forums/viewtop ... s&start=15
If you have anymore questions or concerns, please feel free to post.