Not tested, but I believe a simple cast operator would force the conversion of type char into type int:
Are you sure you have used this method? Try this one out and see if it works:

shape( (int) key, 0, 10, 200, 200 );

See the following thread as well -> http://forum.processing.org/topic/how-to-limit-random-to-integers

Doesn't work. As I said in my original post, I've already tried converting key to an integer and to a float, but my error message is as follows:

Oops! Studying your code better, that shape() method demands these following types:

shape( PShape, float, float, float, float )

What it means is that you have to provide 1 of the variables you declared as PShape for it to work as the 1st argument.

To implement that, you could use the switch/case strategy.

Could you elaborate on what that might entail? Like I said I am new to this...I would really appreciate it.

Hello again Black Obelisk !

I've never dealt w/ PShapes & .svgs before, so I had to search for it! 

Well, I've come up w/ an example, but I guess it's a bit hard for you to understand it.
Gonna retry later for an easier example. For now, try to enjoy it:

private static char keySelect = 0;

private static final byte numPics  = 8;
private static final PShape[] pics = new PShape[numPics];

void setup() {
    size (600, 600);
    smooth();
    
    noLoop();

    for ( byte letter=0; letter<numPics; letter++ )
        pics[letter] = loadShape( char(letter + 'A') + ".svg" );
}

void draw() {
    background (255);

    if (keySelect >= 0 && keySelect < numPics)
        shape( pics[keySelect], 0, 10, 200, 200 );
}

void keyPressed() {
    keySelect = Character.toUpperCase(key);

    if ( keySelect >= 'A' && keySelect < 'A' + numPics )  keySelect -= 'A';
    else keySelect = numPics;
    
    redraw();
}

You are AWESOME! Yes, most of this is pretty much beyond me, but I am definitely going to be taking a good close look at it...thank you! And yes, if you would care to come up with something a bit easier to understand, that would be very much appreciated, but thank you for taking the time to do this. I just ran that your code, and it does exactly what I was trying to do, which is still only a small building block of my bigger picture, but still..

Glad you've liked it!

Problem is that I've abused ASCII code.

To ease your understanding, know that 'A' = 65.

I hope you already know arrays hehe. Since you had svg files from "A.svg" up to "H.svg", so I've decided to make the array pics[8] to store each 1 of them. (range 0 - 7)

pics[letter] = loadShape( char(letter + 'A') + ".svg" );

w/ letter = 0 -> char( letter + 'A' ) -> char( 0 + 65 ) -> char(65) -> 'A' + ".svg" -> "A.svg"
w/ letter = 7 -> char( letter + 'A' ) -> char( 7 + 65 ) -> char(72) -> 'H' + ".svg" -> "H.svg"

Hope it's enough for you to pick it up.