Netdde Errors

It really depends on the error # you are receiving. You could try searchinging www.eventid.net for the eventID number of the netdde error.
Other then that, here is a little something on netdde from Technet article Q228194:

A NETDDE link consistsof two parts, the DDE server program and the DDE client program. The DDE server program contains the data to be shared. The DDE client requests the data from the DDE server, creating a DDE Link. Network DDE requires the server program to make the data accessible on the network. The server program creates a NETDDE share, available over the network, which the client program can connect to. Some examples of NETDDE programs are Microsoft Chat, Microsoft Clip Board Server and Microsoft Hearts.

If your computer has Transport Control Protocol/Internet Protocol (TCP/IP) installed, the computer name can be up to 63 characters long. The computer name should only contain the numbers 0-9, the letters A-Z and a-z, and hyphens. You may use other characters, but doing so may prevent other users or NETDDE programs from finding your computer on the network.