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+The ERROR property is returned when an error occurred processing the PropertyList request. The value of ERROR is a string of numbers in ASCII.
+| Code | Name | Description |
+| ---: | ---- | ----------- |
+|    1 | BAD_USER | User name provided is illega. |
+|    2 | MAX_ORDINARY | World is full. |
+|    3 | MAX_PRIORITY | World is full of priority users. |
+|    4 | BAD_WORLD | World requested is illegal. |
+|    5 | FATAL | Error is fatal and unrecoverable. |
+|    6 | BAD_PROTOCOL | Protocol is unsupported. |
+|    7 | BAD_CLIENTSW | Client version is unsupported. |
+|    8 | BAD_ROOM | Room requested is illegal. |
+|    9 | BAD_SERIAL | Invalid serial number. |
+|   10 | TAKEN_SERIAL | Serial number has already been taken. |
+|   11 | TAKEN_USER | User name has already been taken. |
+|   12 | NO_SUCH_USER | User does not exist. |
+|   13 | BAD_PASSWORD | Invalid password. |
+|   14 | BAD_ACCOUNT | Account is no longer valid. |
+|   15 | NOT_LOGGEDON | User is not logged on. |
+|   16 | BAD_IPADDRESS | IP address is invalid. |
+|   17 | LOGGEDON | User is already logged on. |
+|   21 | ROOM_FULL | The RoomServer is full. |
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