PBP handles the read write bit if I remember correctly, leave your 0 out

this is my code

ADDR=78 PORTBYTE IS VALUE FOR PORTBITS

i2cwrite sda,scl,ADDR,PORTBYTE 'ENSURE ALL OFF ON POWER UP

So I think your code should be

I2CWRITE SDAM,SCLM,%01000000,[%11111111,%11111111] 'enable outputs