diff --git a/pkg/base/lib_map.lua b/pkg/base/lib_map.lua
index 26fdda7..88d6bf8 100644
--- a/pkg/base/lib_map.lua
+++ b/pkg/base/lib_map.lua
@@ -438,7 +438,9 @@ end
 function map_block_pick(x,y,z)
 	local xlen,ylen,zlen 
 	xlen,ylen,zlen = common.map_get_dims()
+	if x < 0 or x >= xlen then return end
 	if y < 0 or y >= ylen then return end
+	if z < 0 or z >= zlen then return end
 	
 	local t = map_pillar_raw_get(x,z)
 	local c = t[y+1]
diff --git a/pkg/base/obj_player.lua b/pkg/base/obj_player.lua
index 013977d..9057fe7 100644
--- a/pkg/base/obj_player.lua
+++ b/pkg/base/obj_player.lua
@@ -714,10 +714,12 @@ function new_player(settings)
 			if this.tool == TOOL_BLOCK and this.blx3 and this.alive then
 				local ct,cr,cg,cb
 				ct,cr,cg,cb = map_block_pick(this.blx3, this.bly3, this.blz3)
-				this.blk_color = {cr,cg,cb}
-				common.net_send(nil, common.net_pack("BBBBB",
-					0x18, 0x00,
-					this.blk_color[1],this.blk_color[2],this.blk_color[3]))
+				if ct ~= nil then
+					this.blk_color = {cr,cg,cb}
+					common.net_send(nil, common.net_pack("BBBBB",
+						0x18, 0x00,
+						this.blk_color[1],this.blk_color[2],this.blk_color[3]))
+				end
 				this.ev_rmb = false
 			elseif this.tool == TOOL_SPADE and this.blx2 and this.alive then
 				if (not this.t_newspade2) then