The use-java-context property is used to determine if the data source is looked up via "java:xxx" or simply "xxx". Remote applications can look up this only via "xxx". EAR and WAR app can look up things via "java:xxx". I'm not sure if RAR can look things up in "java:xxx".
If that does not help, please post your data source lookup code. And post the full error message - copy and paste it (I assume that "objet" is misspelled, which does not help in solving the problem).