This KB article title is a little deceiving because there are several other instances where this multiple CNAME problem occurs.
"When a client computer connects to a Microsoft Windows 2000-based computer or a Microsoft Windows Server 2003-based computer by using an alias name, the client may receive the following error message:
System error 52 has occurred.
A duplicate name exists on the network.
This problem can occur when you try to connect to the server by using a CNAME alias that is created in the DNS zone. For example, this problem may occur with a command similar to the following sample command
net view \\alias.domain name.com where alias is a CNAME record that is created for the server in the domain name.com zone. The server is not "listening" on the alias, and therefore is not accepting connections to that name. "