I had a quick look at the DS.

I think the address you want to use is $68. This is an 8bit I2C address.
I'm pretty sure the reference to $32 7bit address on page 4 is a typo.
In an 8bit address the uppermost 7bits is the actual address and bit 0 is the R/W bit.
With I2Cwrite and I2Cread leave bit0 of the address set as a 0. PBP will deal with bit0 as needed.
So $34 << 1 = $68
%00110100 << 1 = %01101000

I think the command you want to use is this:

I2Cwrite SDA, SCL, $68,["hello"]

The DS seems to indicate you do not need to send an escape char before text, just for commands. Btw the escape is dec 27 not hex 27.

Also the controller wants the master to support clock stretching on the I2C bus so you would need to use the following PBP define.
DEFINE I2C_HOLD 1

Lastly, when you power up the controller, is the SDA bus line pulled high with a pull-up resistor?
The controller needs to see SDA pulled high on power up to set I2C mode instead of serial mode.

Hope I haven't sent you astray!