Media Player -XML playlist

[C# Programming]

hey all
I have this Media Player project
it has albumes' form.
it supposed to add a new song to XML file. but it does not.

here is the source code :
http://rapidshare.com/files/289445150/Homa.rar.html[^ (http://rapidshare.com/files/289445150/Homa.rar.html)]

When download the file and extract , enter form albumes
choose an album from the combobox (e.g album1)
click on "Add" button
select media file.

it does not add it to XML file.

thanks.