Error while programmatically adding a document to SharePoint document library

Question

Hello everyone,
I have created a custom content type and modified the document template to use the quick parts inside the template.
I have a document library which uses the custom content type. 
I have a button inside a custom application page(created using visual studio). On click of this button I want to create a new document inside the document library using the custom content type and update other columns in the content type. I am able to create
the document, but I get the below error when I open the document.
public static void UpdateAndCreateFile(SPWeb web)
try
web.AllowUnsafeUpdates = true;
string sList = "My Document Library";
string sContentType = "My Custom Document";
SPList list = web.Lists[sList];
// this always uses root folder
SPFolder folder = web.Folders[sList];
SPFileCollection fcol = folder.Files;
// find the template url and open
string sTemplate =
list.ContentTypes[sContentType].DocumentTemplateUrl;
SPFile spf = web.GetFile(sTemplate);
byte[] binFile = spf.OpenBinary();
// Url for file to be created
string destFile = fcol.Folder.Url + "/" + "test2.docx";
// create the document and get SPFile/SPItem for
// new document
SPFile addedFile = fcol.Add(destFile, binFile, true);
SPItem newItem = addedFile.Item;
newItem["ContentType"] = sContentType;
newItem.Update();
addedFile.Update();
web.AllowUnsafeUpdates = false;
catch (Exception ex)
// handle exception here
The above code gives the same issue when I use the 'Document' content type instead of the "My Custom Document" content type. 
The document looks/opens fine when I create it from the browser.
Please let me know if you have any suggestions. Thanks.

Answer 1

I could not figure out a proper solution, but here is what I did to get around the issue.
I created a document using the document template and saved it to the library(same doc library) and named it as Sample.docx
In my code, every time I had to create a document, I would just copy the Sample.docx file to the library, but make sure I rename the file when I copy it.
Then I can use the url of the file I saved through my code and get the list item and update the other properties/columns of the content type
Below is the code to use an existing file and create a new file
public static void UpdateAndCreateFile(SPWeb web)
try
web.AllowUnsafeUpdates = true;
string sList = "My Documents";
SPList list = web.Lists[sList];
// this always uses root folder
SPFolder folder = web.Folders[sList];
SPFileCollection fcol = folder.Files;
SPFile file = fcol[sList + "/Sample.docx"] ;
file.CopyTo(sList + "/" + "test1.docx", true);
web.AllowUnsafeUpdates = false;
catch (Exception ex)
Thanks.