Today Microsoft released an update to the Visual FoxPro DDEX Provider Example.

From Milind's post:
The original VFPDDEX sample did not include a license ID for Visual Studio. This required the user to register with Visual Studio Extensibity program, get a package load key (PLK) and update the provider with the new key.

This download fixes this problem. The sample includes the PLK in the resource of the provider. The dowload also contains source code for registering the provider.

http://msdn.microsoft.com/en-us/vfoxpro/bb264582.aspx