Creating XML nodes based on a tab count from input file using XPath

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C#

XPath

I am trying to create an XML document as output using C# with the parent node being based on the count of tabs from the input file. I am trying to use XPath to determine the parent node. I have read the source file in and saved it as a list, and I am able to get the parts of the data saved as the attributes that I need, but the child nodes are not in the expected order. It is putting them in the expected "level", but not under the correct parent. My XPath seems to not be getting the parent that I expect it to, but I am not sure what is wrong with the XPath. It seems to work down to Filename8 (in the example), but it would put Filename9 under Filename 7 and then Filename8 would be found lower down in the tree. Of course this is a small sample of the input file, but I hope you will understand what I am trying to do. Any suggestions would be greatly appreciated!
Here is part of my code:

//Loop through the list to create the child nodes
            for (int i = 0; i < lines.Count; i++)
            {
              // if the line starts with /* then it is a comment, 
              // skip and go to next line
                if (lines[i].StartsWith("/*"))
                {
                    continue;
                }
                tabCount = 0;
                tabCount = lines[i].Count(c => c == '\t');  

                //get the title of the line
                if (lines[i].Contains("/*"))
                {
                    titleIndex = lines[i].IndexOf("/*");
                    endTitleIndex = lines[i].IndexOf("*/");
                    title = lines[i].Substring(titleIndex + 2, endTitleIndex - titleIndex - 2).Trim();
                }
                else
                {
                    titleIndex = lines[i].Length;
                }

                //get the file name
                filename = lines[i].Substring(0, titleIndex).Trim();

                //create the element and add the filename attribute
                XmlElement tocEntry = doc.CreateElement("tocEntry");   
                tocEntry.SetAttribute("filename", filename);
                
                //if the title not blank add title attribute
                if (title.Length > 0)
                {
                    tocEntry.SetAttribute("title", title);
                }

                //Add in a tabCount attribute to help determine the parent node.
                tocEntry.SetAttribute("tabCount", tabCount.ToString());

                //If the tabCount is 0 then add the node to the root
                if (tabCount == 0)
                {
                    root.AppendChild(tocEntry);
                }
                //If the tabCount is not 0 then add as a child to the parent.
                else 
                {
                    XmlNode parent = root.SelectSingleNode("//tocEntry[@tabCount='" + (tabCount - 1) + "'][last()]");
                    parent.AppendChild(tocEntry);
                }               
               
            }

Here is a small sample of the input file:
..\filename1.xml /* TITLE 1 */
/t..\filename2.xml /* TITLE 2 */
/t/t..\filename3.xml /* TITLE 3 */
/t/t..\filename4.xml /* TITLE 4 */
/t/t..\filename5.xml /* TITLE 5 */
/t/t..\filename6.xml /* TITLE 6 */
/t/t..\filename7.xml /* TITLE 7 */
/t..\filename8.xml /* TITLE 8 */
/t/t..\filename9.xml /* TITLE 9 */
/t/t/t..\filename10.xml /* TITLE 10 */
/t/t/t/t..\filename11.xml /* TITLE 11 */

Desired output sample:

<Entry filename="..\filename1.xml" title="TITLE 1">
     <Entry filename="..\filename2.xml" title="TITLE 2">
        <Entry filename="..\filename3.xml" title="TITLE 3"/>
        <Entry filename="..\filename4.xml" title="TITLE 4"/>
        <Entry filename="..\filename5.xml" title="TITLE 5"/>
        <Entry filename="..\filename6.xml" title="TITLE 6"/>
        <Entry filename="..\filename7.xml" title="TITLE 7"/>
     </Entry>
     <Entry filename="..\filename8.xml" title="TITLE 8">
        <Entry filename="..\filename9.xml" title="TITLE 9">
           <Entry filename="..\filename10.xml" title="TITLE 10">
               <Entry filename="..\filename11.xml" title="TITLE 11"/>
           </Entry>
        </Entry>
     </Entry>
 </Entry>