Handle missing frames for sprite gracefully

src/r_skins.c

@@ -534,7 +534,7 @@ static void R_LoadSkinSprites(UINT16 wadnum, UINT16 *lump, UINT16 *lastlump, ski
 		R_AddSingleSpriteDef(spr2names[sprite2], &skin->sprites[sprite2], wadnum, *lump, *lastlump);
 
 	if (skin->sprites[0].numframes == 0)
-		I_Error("R_LoadSkinSprites: no frames found for sprite SPR2_%s\n", spr2names[0]);
+		CONS_Alert(CONS_ERROR, M_GetText("No frames found for sprite SPR2_%s\n"), spr2names[0]);
 }
 
 // returns whether found appropriate property