So, I think I hit a limitation of MEL, but if there's a simple solution out there, it doesn't hurt to ask.

I was trying to animate the CVs of curve like so:

proc animateCurve( int $numFiles, int $numLines ) 
{
    // Set keys for all CVs of the input curve.
    for ( $i = 1 ; $i < $numLines ; $i++ )
    {
        setKeyframe "curveShape1.cp[$i].xv";
        setKeyframe "curveShape1.cp[$i].yv";
        setKeyframe "curveShape1.cp[$i].zv";        
    }
}

The problem with this is using variables to access an index doesn't seem to be possible (constants work fine). I've figured out a slight work around using expressions (tying the CVs values to the translate attributes of a locator), but if there's an easier workaround, I'd appreciate it much. This has to be in one entire script for this particular use, and it has to be in MEL.