When you do this
"If I try to use 5 volts to the SD21 and simply use the SDA/SCL from the Ardunio the sketch hangs, the 1st time it attempts to end the transmission. "
are you connecting the 2 grounds together?
No actually I am not, to connect the grounds, I am assuming the ground on the SD21 will go to ground on the Arduino, does it matter which one ? I am assuming you would go to the ground beside the 5 volt pin ?