How to find out what is wrong in test case during importing it to TFS 2010 - testcase

Question

I'm importing test cases from xml file to TFS2010 and get an exception. But there is no info about what definitely is incorrect.
"Work item 0 is invalid and cannot be saved. Exception: 'TF237124: Work Item is not ready to save'."
How is it possible to determine what is wrong in imported data from xml?
using System.Text.RegularExpressions;
using System.Xml;
using Microsoft.TeamFoundation.Server;
using Microsoft.TeamFoundation.WorkItemTracking.Client;
using System;
using System.Linq;
internal class Program
{
// Input File
private static TestLink testLink = new TestLink("E:\\dev\\TestLinkToTfs\\testsuites.xml");
// Target TFS server
private static Tfs tfs = new Tfs("http://host:8080/tfs/Test", "Test");
private static void Main(string[] args)
{
var testLinkTestCase = testLink.GetTestCases().Take(1).ToList();
var steps = testLinkTestCase.Descendants("step");
var testCase = tfs.Project.TestCases.Create(tfs.Project.WitProject.WorkItemTypes["Test Case"]);
testCase.Title = testLinkTestCase.Attribute("name").Value;
var summary = testLinkTestCase.Descendants("summary").ToList();
var issueId = TestLink.GetLinkedIssueId(summary);
var regEx = new Regex(#"[^a-zA-Z0-9 -]");
var grandParentName = regEx.Replace(testLinkTestCase.Parent.Parent.Attribute("name").Value, string.Empty);
var parentName = regEx.Replace(testLinkTestCase.Parent.Attribute("name").Value, string.Empty);
var area = string.Format(#"Test\Test Cases\{0}\{1}", grandParentName, parentName);
testCase.CustomFields["Assigned To"].Value = string.Empty;
testCase.Area = area;
Tfs.AddSteps(steps, testCase);
testCase.Save();
}
Console.ReadKey();
}
}
}

Answer 1

When the Work Item id is 0 means that this is created dynamically and some field values are not valid. You should try the method
workitem.validate();
before you save the Work Item and then try to debug you code. This will tell you the exact fields that have invalid data.
I could be more helpful if you post the code and the xml that you use for this.