Mosu, thanks for the information.
With other clients, Pidgin for example, works correctly.
When I try to use Plucs with IM Spark, he presents authentication error.
Analyzing the errors tend to think I can be the Java version, since Spark depends JRE.
I installed an older version of the JRE, but still also having errors.
In this case I ask you, when is the JRE version are you using there on your device?