Hooking it to a car battery is one of the quietest ways of powering an arduino.
Just make sure the battery isn't connected to a car.

DPTD

sp. "DPDT"  aka "double-pole, double-throw"

You need to get the manufacturer's code off the relay to get the contact rating (the sort of voltages and currents it will switch).
It will probably be OK with 12V up to maybe a couple of amps.

No, the pullups are built-in, but you're not using them.
http://arduino.cc/en/Reference/DigitalWrite
On the other hand, you don't say how the tiles are wired.

Could be pull-ups , or lack of.

Can I suggest you read about arrays?

Did you really cut and paste?

Those should be underscores in the variable name, not dashes.

I unplugged the board from the power source (USB only).
On the unplugged board i pressed the reset-button and kept pressing it.
I compiled the sketch and hit CTRL-U, while still holding down the reset-button.
Once the RX-led blinks once (very fast) i let go of the reset-button, resulting in a completed and succesful upload. The sketch is performed without problems...

How does an LED flash on an unpowered board?

9600 is the speed, not a port number

Well, sending (from the Arduino) is blocking, so the function won't return until the last character has been sent.
Receiving is buffered, so up to 128 characters will be received before characters are lost.

Try some of the examples.

See "Communication" here.
http://arduino.cc/en/Tutorial/HomePage

Try some of the examples.

i need to work on my grammer

Oh, the irony.   ;D

So what you're saying is sparkies are not expected to communicate effectively with the rest of us?

Good luck with your future career.

Paragraph breaks.
I really like paragraph breaks.    ;D

And use of the "shift" key.

it needs to be conveted to C/C++

i could do that

 :o

Good luck - it's been compiled into machine code, not ASCII source.
That you had to ask the question makes me suspect you won't succeed.

The hex doesn't look anything like source C/C++.

What do your tutors/lecturers/instructors think?