This book was published in Dec 01 which means it was written using .NET Beta 2. It is now completely out of date and many of the examples just don't work. To be fair, there is an "Update" document available for download from Wrox but wht not just buy an up to date book in the first place. My recommendation is "Applied XML Programming for Microsoft .NET" by Dino Esposito, # 0735618011.