Hi
I'm build an android application that apply snmp get operation on router but the result is null and this is the error message
Error Sending PDU. IO error sending PDU. Send Error: null
this is my code :

2. package com.example.snmptst;
3. 
   
4. import com.adventnet.snmp.beans.SnmpTarget;
5. import android.os.Bundle;
6. import android.app.Activity;
7. import android.view.Menu;
8. import android.widget.Toast;
9. 
   
10. public class MainActivity extends Activity {
11. 
    
12.     @Override
13.     protected void onCreate(Bundle savedInstanceState) {
14.         super.onCreate(savedInstanceState);
15.         setContentView(R.layout.activity_main);
16.         
17. SnmpTarget target;
18. String targetHost;
19. int targetPort;
20. String community;
21. int timeout;
22. int retries;
23.    String returnString = null;    
24.    targetHost = "192.168.1.104";
25. targetPort = 161;
26. community = "public";
27. timeout = 5000;
28. retries = 2; //No I18N
31. // Use an SNMP target bean to perform SNMP operations
32. target = new SnmpTarget();
33. target.setTargetHost(targetHost); // set the agent hostname
34. if(community != null) { // set the community if specified
35. target.setCommunity(community);
36. }
37. target.setTargetPort(targetPort); // set the port, default is 161
39. // set the timeout/retries parameters, default are 5 and 0
40. target.setTimeout(timeout);
41. target.setRetries(retries);
42. // Create oidList array from the obtained arrayList
43. String []oidList = new String[1];
44. oidList[0]=".1.3.6.1.2.1.1.5.0";
45. // Set the OID List on the SnmpTarget instance
46. target.setObjectIDList(oidList);
48. String[] result = target.snmpGetList(); // do a get request
50. // Return the result/error from the response.
51. if(result != null) {
52. String successString = "Response received.  Values:\n"; //No I18N
53. for(int k=0; k<result.length; k++) {
54. successString = successString + target.getObjectID(k) + " : " + result[k] + "\n"; //No I18N
55. }
56. returnString = successString;
57. } else {
58. String errorString = "Request Failed or Timed-out. \n"; //No I18N
59. errorString = errorString + target.getErrorString();
60. returnString = errorString;
61. }
62. Toast.makeText(getApplicationContext(), returnString, Toast.LENGTH_LONG).show();
63.        
64.    }
65. 
    
66. 
    
67.     @Override
68.     public boolean onCreateOptionsMenu(Menu menu) {
69.         // Inflate the menu; this adds items to the action bar if it is present.
70.         getMenuInflater().inflate(R.menu.main, menu);
71.         return true;
72.     }
73.     
74. }

Any one can help me?
Thanks.