diff --git a/src/main/java/cz/ceskydj/netherwater/database/DB.java b/src/main/java/cz/ceskydj/netherwater/database/DB.java
index 3a16794..c95db83 100644
--- a/src/main/java/cz/ceskydj/netherwater/database/DB.java
+++ b/src/main/java/cz/ceskydj/netherwater/database/DB.java
@@ -306,12 +306,38 @@ public OfflinePlayer getDispenserOwner(Block dispenser) {
             query.setString(4, dispenser.getWorld().getName());
 
             ResultSet resultSet = query.executeQuery();
-            // Get first result item
-            resultSet.next();
+            // Get first result item (if there is any)
+            if (!resultSet.next()) {
+                this.messageManager.dump("Found unregistered dispenser block (not found in DB) on [" + dispenser.getX() + ", " + dispenser.getY() + ", " + dispenser.getZ() + "]");
 
-            String playerUUID = resultSet.getString("player");
+                return null;
+            }
+
+            try {
+                String stringyPlayerUUID = resultSet.getString("player");
+                if (stringyPlayerUUID == null) {
+                    this.messageManager.dump("Found corrupted dispenser record in DB (column player has value NULL) for dispenser on [" + dispenser.getX() + ", " + dispenser.getY() + ", " + dispenser.getZ() + "]. Removing...");
+                    this.deleteDispenser(dispenser);
+
+                    return null;
+                }
 
-            return Bukkit.getOfflinePlayer(UUID.fromString(playerUUID));
+                UUID playerUUID = UUID.fromString(stringyPlayerUUID);
+                OfflinePlayer player = Bukkit.getOfflinePlayer(playerUUID);
+                if (player.getName() == null) {
+                    this.messageManager.dump("Found registered dispenser with unknown owner (player couldn't been found using stored UUID) on [" + dispenser.getX() + ", " + dispenser.getY() + ", " + dispenser.getZ() + "]. Removing...");
+                    this.deleteDispenser(dispenser);
+
+                    return null;
+                }
+
+                return player;
+            } catch (IllegalArgumentException e) {
+                this.messageManager.dump("Found registered dispenser with invalid player UUID on [" + dispenser.getX() + ", " + dispenser.getY() + ", " + dispenser.getZ() + "]. Removing...");
+                this.deleteDispenser(dispenser);
+
+                return null;
+            }
         } catch (SQLException e) {
             this.messageManager.dump("DB error: " + e.getMessage());
 
diff --git a/src/main/java/cz/ceskydj/netherwater/listeners/WaterDispenseListener.java b/src/main/java/cz/ceskydj/netherwater/listeners/WaterDispenseListener.java
index af4caaf..6b09c01 100644
--- a/src/main/java/cz/ceskydj/netherwater/listeners/WaterDispenseListener.java
+++ b/src/main/java/cz/ceskydj/netherwater/listeners/WaterDispenseListener.java
@@ -61,7 +61,11 @@ public void onBlockDispense(BlockDispenseEvent event) {
         this.messageManager.dump("- Block's metadata: " + block.getBlockData().getAsString(true));
         this.messageManager.dump("- Item: " + item.getType().name());
         this.messageManager.dump("- Item's metadata: " + item.getItemMeta());
-        this.messageManager.dump("- Responsible player: " + player + (fromDb ? "(from DB)" : ""));
+        if (player != null) {
+            this.messageManager.dump("- Responsible player: " + player.getName() + (fromDb ? " (from DB)" : ""));
+        } else {
+            this.messageManager.dump("- Responsible player: unknown (no closed player and dispensed isn't registered)");
+        }
 
         if (block.getType() != Material.DISPENSER) {
             return;