KeePassRPC 1.7.2 displays error message when logging in

If KeePass shows you an error popup message like the one below when you enter your KeePass master key, please check the version of KeePassRPC you are running and upgrade to at least version 1.7.

Example one
ERROR! Please click on this box, press CTRL-C on your keyboard and paste into a new post on the KeeFox forum (http://keefox.org/help/forum). Doing this will help other people to use KeeFox without any unexpected error messages like this. Please briefly describe what you were doing when the problem occurred, which version of KeeFox, KeePass and Firefox you use and what other security software you run on your machine. Thanks! Technical detail follows: System.NullReferenceException: Object reference not set to an instance of an object
_ at KeePassRPC.KeePassRPCClientConnection.Encrypt (System.String plaintext) <0x4081cde0 + 0x00128> in :0 _
_ at KeePassRPC.KeePassRPCClientConnection.Signal (Signal signal, System.String methodName) <0x4081bb90 + 0x002a3> in :0_

Example two
ERROR! Please click on this box, press CTRL-C on your keyboard and paste into a new post on the KeeFox forum (http://keefox.org/help/forum). Doing this will help other people to use KeeFox without any unexpected error messages like this. Please briefly describe what you were doing when the problem occurred, which version of KeeFox, KeePass and Firefox you use and what other security software you run on your machine. Thanks! Technical detail follows: System.NullReferenceException: Az objektumhivatkozás nincs beállítva semmilyen objektumpéldányra.
_ a következő helyen: KeePassRPC.KeePassRPCClientConnection.Encrypt(String plaintext)_
_ a következő helyen: KeePassRPC.KeePassRPCClientConnection.Signal(Signal signal, String methodName)_

It is possible for this message to appear for other reasons so if upgrading to 1.7.3 or higher does not fix the problem please start a new topic and provide more information about what you were doing just before the error message appeared.

Note that 1.7.3 is the version of KeePassRPC, not the version of Kee (or KeeFox).

Fix is to upgrade to 1.7.3.