Can an API search cause Splunk to hang?

Hello,

we are using currently Splunk 3.4.4. and trying to commit a search via the REST API.

Our problem is that if we are using the term:

SearchJob job = smgr.dispatchAndWait(jp);

it causes Splunk to stop working properly. Login is not possible anymore then to the web interface, data is not getting indexed, the system is basically "halting".

Here is the Code we are using:

String hostUrl = "";
String query = "error | head 10";
BasicConfigurator.configure();

SplunkClient client = new SplunkClient(hostUrl);
client.login(user, password);

SearchManager smgr = client.getSearchManager();
JobParameters jp = new JobParameters();
jp.Search = query;

Calendar c = Calendar.getInstance();
c.set(Calendar.HOUR_OF_DAY, 0);
c.set(Calendar.MINUTE, 0);
c.set(Calendar.SECOND, 0);
c.set(Calendar.MILLISECOND, 0);
c.set(Calendar.DAY_OF_WEEK, Calendar.SUNDAY);
jp.setEarliestTime(c.getTime());
c.set(Calendar.DAY_OF_WEEK, Calendar.SATURDAY);
jp.setLatestTime(c.getTime());

SearchJob job = smgr.dispatchAndWait(jp);

CookedParameters cp = new CookedParameters();
List<String> fields = new ArrayList<String>();
fields.add("_raw");
fields.add("_time");
cp.FieldList = fields;

cp.Count = 100;
JsonArray jsa = job.getCookedResultsJSON(cp);
System.out.println(jsa);

if( jsa.size() > 5 )

System.out.println(jsa.get(5).getAsJsonObject().get("_raw"));

// Dismiss the search job to free resources
job.controlJob("cancel", "");

What is it that we are doing wrong?