Problem with FIELD_INDEX_ENTRY

Hi, I have problem with index_entry field. If you look at following code:
Document document = new Document(inputStream);

Section section = document.getFirstSection();

Body body = section.getBody();

Paragraph paragraph = (Paragraph) body.getChild(NodeType.PARAGRAPH, 3,
false);

NodeCollection nodeCollection = paragraph.getChildNodes();

StringBuffer codeBuffer = new StringBuffer();

Run code = (Run) nodeCollection.get(2);

codeBuffer.append(code.getText());

Run code2 = (Run) nodeCollection.get(3);

codeBuffer.append(code2.getText());

Run code3 = (Run) nodeCollection.get(4);

codeBuffer.append(code3.getText());

DocumentBuilder builder = new DocumentBuilder(document);

builder.moveToDocumentEnd();

builder.insertField(codeBuffer.toString(), “”);

document.save(“d:/output.doc”);

I just read code from field and write it down again.

In the output document you will see a upright dash in the place of inserted field.

There is attached test document.

I am using slides for java. Can you tell me what is the problem?

Thanks, Ivica.