Do You see the energy_sprite at the start?
If You see the energy_sprite - have you called the function init_animsprite() so that the sprite could animate?


If somebody needs Lite-C code, here it is.
(Tested and worked) whistle
The only thing that was missing FLAG2 = VISIBLE wink

Click to reveal..
Code:
BMAP* panel_pcx = "panel.pcx";

PANEL* energy_pan = // background panel
{
	bmap = panel_pcx;
	layer = 20;	
	pos_x = 0;
	pos_y = 0;
	flags = D3D | OVERLAY | VISIBLE;
}

ENTITY* energy_sprite =
{ 
	type = "energy+10.pcx"; 
	layer = 25; 
	view = camera; 
	x = 350; 
	y = 134; 
	z = 100; 
	flags = BRIGHT | TRANSLUCENT;
	flags2 = VISIBLE;
} 

function init_animsprite() 
{ 
	while (1) 
	{ 
		energy_sprite.frame += 0.5 * time_step; 
		if (energy_sprite.frame > 10) 
		{
			energy_sprite.frame %= 10; // loop
		}
		wait (1); 
	} 
}