[javac] D:\real_drftpd\src\net\thirdparty\plugins\irc\AsyncResponseUptime.ja
va:7: cannot access org.drftpd.slave.async.AsyncResponse
    [javac] bad class file: D:\real_drftpd\classes\org\drftpd\slave\async\AsyncR
esponse.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.