Ah, the Adafruit #292, oops that is the backpack I meant rather than #210.
That is is the board I was talking about earlier.
It can run in "i2c" mode or "spi" mode.
That board uses a MCP23008, so none of the more common "LiquidCrystal_I2C" libraries floating
around will work, since they only support the PCF8574 chip.
That board also doesn't really have a SPI interface, it has a 74HC595 on it and
uses a 3 wire shift register interface - which is not SPI.
You have a few choices, you can use the Adafruit MCP23008 i2c library
(which Adafruit supplies, you just need to go to their site, download and install it)
or you could re-strap the board (requires soldering a jumper) and run it in shift register
mode - which Adafruit calls "SPI" mode. You can see the solder jumper on the board
labeled "SPI Enable" which must be soldered to disable i2c and enable shift register mode.
If you run it in shift register mode, you will need to download and install fm's library.
Then use this constructor:
LiquidCrystal_SR3W lcd(DatPin, ClkPin, LatPin, 2,0,1,6,5,4,3,7, POSITIVE);
I also have a unreleased i2c interface class for fm's library that supports the MCP2308,
however, since it appears you have limited h/w & s/w experience, I'd recommend using the
adafruit library and if you have any issues go over to the adafruit tech forum http://www.adafruit.com/support
and get support from her. She is very good about supporting her products.
One thing that is very different when using the adafruit library is that the "address"
you supply isn't really the i2c address. It is the value you have jumpered.
So make sure to only fill in the jumpered address (a value zero to seven) vs the actual i2c address
if you don't, then the library will use address 0x27, which with a default board will be wrong.
(I think this is a very dumb way of doing things, and I reported it to Adafruit)