I'm not 100% sure, as my lab isn't cooperating with me at present - but I believe this has to do with whether an SMP profile you've added to your Workflow Explorer Credentials tab is able to authenticate to the Workflow repository. I believe the SMP's installed solutions are then reported to the Workflow Solution Center, and that any template/demo projects that apply to your installed solutions are made available there.
For example, if you're able to authenticate to the repository, and you have Patch Management installed, there should be a Zero Day Patch demo.
Again, I'm presently unable to confirm, and thereby I could be completely incorrect, but perhaps give that a check and ensure that your workflow environment is configured properly on your SMP. I'll see if i can get more info for you.