can't call "sadd" sequentially

[XiaoZhiming]

JRedis client = new JRedisClient("host-name", port);
client.sadd("a", "AAA");
client.sadd("b", "BBB");

-- JREDIS -- ERROR: Error response for SADD => ERR unknown command 'AAA'
Exception in thread "main" Exception on [SADD] => ERR unknown command 'AAA'
at org.jredis.ri.alphazero.connection.SynchConnection.serviceRequest(SynchConnection.java:169)
at org.jredis.ri.alphazero.JRedisClient.serviceRequest(JRedisClient.java:155)
at org.jredis.ri.alphazero.JRedisSupport.sadd(JRedisSupport.java:259)
at org.jredis.ri.alphazero.JRedisSupport.sadd(JRedisSupport.java:269)
at test.Main.main(Main.java:73)
Java Result: 1

[alphazero]

Note for anyone else who stumbles on this pattern of error: Make sure your JRedis and Redis versions are compatible.