It looks like there was a revamp of the graphics engine used by the Touchshield Stealth/Slide at one point and the code to support backwards compatibility is missing for function lcd_rect().
Navigate to the Antipasto IDE directory: C:\Antipasto\hardware\arduino\cores\touchshield\src\components\board.
Open SubPGraphics.cpp with your favorite editor and add the following code just below the lcd_rectangle() function.
//*******************************************************************************
void lcd_rect(LCD_RECT rect, COLOR outline_color, COLOR fill_color)
{
bcolor = fill_color;
fcolor = outline_color;
gFillEnb = true;
drawrect(rect.left, rect.top, (rect.right - rect.left), (rect.bottom - rect.top));
}