Ich hab mir erlaubt deinen Code zu formatieren und ein bisschen zu vereinfachen (ganzen ifs rausgenommen)
Falls irgendwas nicht so funktioniert wie du wolltest, einfach hier nochmal posten, hab den code nicht getestet.

Code:

var inventar_mode = 1;

entity energy_sprite
{
	type = <energy+10.pcx>;
	layer = 25;
	view = camera;
	x = 500;
	y = 142;
	z = 180;
	flags = visible, flare, bright;
}


text nachricht1
{
	font = schrift;
	layer = 15;
	pos_x = 300;
	pos_y = 680;
	string = "Moechten sie das nemmen";
	Flags = narrow,center_x;
}

panel leben
{
	bmap = lebense;
	layer = 17;
	pos_x = 300;
	pos_y = 100;
	flags = visible;
}

panel schirm
{
	bmap = bildschirm;
	layer = 16;
	pos_x = 180;
	pos_y = 250;
	flags = visible;
}

panel sprechpanel
{
	bmap = sprech;
	layer = 14;
	pos_x = 180;
	pos_y = 600;
	flags = visible;
}

panel inve
{
	bmap = inventar1;
	layer = 13;
	pos_x = 700;
	pos_y = 250;
	flags = visible;
}

panel hintergrund
{
	bmap = schwarz;
	layer = 10;
	pos_x = 200;
	pos_y = 200;
	flags = visible;
}

panel dat
{
	bmap = datei1;
	layer = 11;
	pos_x = 700;
	pos_y = 100;
	flags = visible;
}

panel einaus_panel
{
	layer = 12;
	pos_x = 600;
	pos_y = 100;
	flags = visible;
	bmap = karte1;
}


function init_animsprite()
{
	energy_sprite.visible = on;
	
	while (inventar_mode)
	{
		energy_sprite.frame += 0.3 * time;
		if (energy_sprite.frame > 10)
		{
			energy_sprite.frame %= 10; // loop
		}
		wait (1);
	}
	
	energy_sprite.visible = off;
}


function panel_einaus()
{
//einaus_panel.pos_x = 0;
//einaus_panel.pos_y = 0;
//einaus_panel.scale_x = screen_size.x/bmap_width(karte1);
//einaus_panel.scale_y = screen_size.y/bmap_height(karte1);

//dat.pos_x = 0;
//dat.pos_y = 0;
//dat.scale_x = screen_size.x/bmap_width(datei1);
//dat.scale_y = screen_size.y/bmap_height(datei1);

	inventar_mode = !inventar_mode;
	
	hintergrund.pos_x = 0;
	hintergrund.pos_y = 0;
	hintergrund.scale_x = screen_size.x/bmap_width(schwarz);
	hintergrund.scale_y = screen_size.y/bmap_height(schwarz);	

	hintergrund.visible = inventar_mode;
	leben.visible = inventar_mode;
	nachricht1.visible = inventar_mode;
	schirm.visible = inventar_mode;
	inve.visible = inventar_mode;
	dat.visible = inventar_mode;
	sprechpanel.visible = inventar_mode;
	
	init_animsprite();
} 

on_t = panel_einaus;