I get a Notice when trying to run Explore in Analysis. There is no output. The problem seems to have something to do with a matrix in my Volume at Price code. As far as I can tell, my code closely resembles the code on the AB website at https://www.amibroker.com/guide/afl/pricevoldistribution.html. This code also gives me a Notice in Analysis. Here is the Notice for my code: 
My VAP code:
// VAP
_SECTION_BEGIN( "Volume At Price (VAP)" );
showVAP = ParamToggle( "Show VAP", "No|Yes", 1 );
showMonth = ParamToggle( "Show Month/Year VAP", "No|Yes", 0 );
nbins = Param( "Bins", 15, 3, 100, 1 );
pRecHeight = 0.9; //Param( "Rectangle Height", 0.90, 0.10, 1, 0.05 );
fontSize = 7; //Param( "Font Size", 7, 3, 15, 1 );
fontColor = colorWhite; // ParamColor( "Font Color", colorWhite );
bi = BarIndex();
fvb = FirstVisibleValue( bi );
lvb = LastVisibleValue( bi );
// Classify volume into three bins - top, middle and bottom thirds
BullBearZone = ( H - L ) / 3;
bullbar = C > ( H - BullBearZone );
bearbar = C < ( L + BullBearZone );
// mx = [row 0][col 0]
// price levels in first column [0][0] and relative volume at that level in second column [0][1]
// https://www.amibroker.com/guide/afl/pricevoldistribution.html
mx = PriceVolDistribution( H, L, V, nbins, True, fvb, lvb ); // Total vol all bars
mx1 = PriceVolDistribution( H, L, IIf( bullbar, V, 0 ), nbins, True, fvb, lvb ); // Tot vol in upper 1/3 of candle
mx2 = PriceVolDistribution( H, L, IIf( bearbar, V, 0 ), nbins, True, fvb, lvb ); // Tot vol in lower 1/3 of candle
// PlotVAPOverlay
nbins = MxGetSize( mx, 0 );
nbins1 = MxGetSize( mx1, 0 );
nbins2 = MxGetSize( mx2, 0 );
GfxSetOverlayMode( 1 );
GfxSetCoordsMode( 1 );
if( showVAP )
{
if( nbins > 1 && nbins == nbins1 && nbins == nbins2 )
{
MaxVolume = mx[ 0 ][ 1 ]; // Column = 1
// find max volume in col 1 and associated price in col 0
for( i = 1; i < nbins; i++ )
{
if( mx[ i ][ 1 ] > MaxVolume )
{
MaxVolume = mx[ i ][ 1 ]; // Volume for that bin 1...
MaxVolume = IIf( MaxVolume > 0, MaxVolume, 0.001 );
}
}
// rectangle height
RecHeight = ( mx[ 1 ][ 0 ] - mx[ 0 ][ 0 ] ) / 2 * pRecHeight;
GfxSelectFont( "Arial", fontSize ); // Change the text size here
for( i = 0; i < nbins; i++ )
{
// mx1 = Bull volume - close in upper 1/3 of candle
price = mx1[ i ][ 0 ]; // price level
absVolume = mx1[ i ][ 1 ];
absVolume = IIf( absVolume > 0, absVolume, 0.001 );
VolAcum = absVolume;
relvolume1 = absVolume / MaxVolume;
relbar = relvolume1 * ( lvb - fvb + 1 );
// upper left ner of the rectangle.
x1 = fvb;
y1 = price + RecHeight;
// lower right ner of the rectangle.
x2 = fvb + relbar;
y2 = price - RecHeight;
bullColor = ColorBlend( colorSeaGreen, GetChartBkColor(), 0.6 );
GfxFillSolidRect( x1, y1, x2, y2, bullColor );
GfxSetBkColor( bullColor );
GfxSetTextColor( colorWhite );
GfxTextOut( NumToStr( round( relvolume1 * 100 ), 2.0 ) + "%", x1, y1 );
// mx2 = Bear volume - close in lower third of candle
absVolume = mx2[ i ][ 1 ];
VolAcum += absVolume;
relvolume2 = absVolume / MaxVolume;
relbar2 = relvolume2 * ( lvb - fvb + 1 );
x1 = x2;
x2 = x1 + relbar2;
bearColor = ColorBlend( colorCustom16, GetChartBkColor(), 0.6 );
GfxFillSolidRect( x1, y1, x2, y2, bearColor );
GfxSetBkColor( bearColor );
GfxSetTextColor( colorWhite );
GfxTextOut( NumToStr( round( relvolume2 * 100 ), 2.0 ) + "%", x1, y1 );
// mx = All Bars
absVolume = mx[ i ][ 1 ];
relvolume3 = ( absVolume - VolAcum ) / MaxVolume;
if( relvolume3 > 0 ) // Remove zeros as this interferes with Price below
{
relbar3 = relvolume3 * ( lvb - fvb + 1 );
x1 = x2;
x2 = x1 + relbar3;
midColor = ColorBlend( colorGrey40, GetChartBkColor(), 0.2 );
GfxFillSolidRect( x1, y1, x2, y2, midColor );
GfxSetBkColor( midColor );
GfxSetTextColor( colorWhite );
GfxTextOut( NumToStr( round( relvolume3 * 100 ), 2.0 ) + "%", x1, y1 );
}
// Output Price at the end of the histogram
GfxSetBkColor( colorBlack );
GfxSetTextColor( colorAqua );
GfxTextOut( NumToStr( round( Price / 100 ), 2.0 ), x2 + 1, y1 );
// Plot Support & Resistance lines
a = round( relvolume1 * 100 );
b = round( relvolume2 * 100 );
d = round( relvolume3 * 100 );
Diff = IIf( a >= 0 AND b >= 0, abs( a - b ), 0 );
if( Diff >= 0 AND Diff <=2 )
Plot( Price, "", colorDarkOliveGreen, styleDashed | styleNoLabel );
if( a + b + d > 98 )
{
pctMTZ = round( ( ( C - Price ) / Price ) * 100 );
Plot( Price, "\nVAP MTZ(" + pctMTZ + "%)", colorAqua, styleDashed, Null, Null, 2, -1, 1 );
}
}
}
}
if( showMonth )
{
segments = IIf( Interval() == inDaily, Month(), Year() );
segments = segments != Ref(segments , -1 );
PlotVAPOverlayA( segments, nbins * 2, 95, ColorBlend( colorLightBlue, colorBlack, 0.5 ), 4 );
}
// VAP Interpretation
printf( "<b>\nVOLUME AT PRICE (VAP)</b>" );
printf( "\nVAP shows total volume of trading that occurred at given price level. VAP is calculated from data bars that are currently visible.\nThe longest bars show the most traded zone.\nBars are divided into thirds acding to the Close in lower, mid and upper thirds.\n" );
_SECTION_END();
I would greatly appreciate any insights / solutions.
(Using AB v6.39.1 on a PC with an AMD Ryzen 16 core with 16GB RAM and 64 bit software.)