[javac] D:\real_drftpd\src\org\drftpd\slave\Slave.java:83: cannot access com
.Ostermiller.util.StringTokenizer
    [javac] bad class file: D:\real_drftpd\lib\slave.jar(com/Ostermiller/util/St
ringTokenizer.class)
    [javac] class file has wrong version 50.0, should be 49.0
    [javac] Please remove or make sure it appears in the correct subdirectory of
 the classpath.
    [javac] import com.Ostermiller.util.StringTokenizer;
    [javac]                             ^
    [javac] 1 error