There is bug with workflows in PowerShell v3 that you might run into. I kept banging into it until I tracked it down. Â The problem occurs if you try to run a workflow from a PSDrive that you have added. For example, I have a PSDrive (S) which is mapped to C:\Scripts. When I try to run a workflow from this drive, I will get an error.
The workaround is to simply change to your C: drive, or any PSDrive that PowerShell loads by default. Then the workflow will run.
This has been filed on Connect but I thought I’d share the workaround so you don’t have to bang your head. And if you are curious about workflows, there will be a good chapter in the forthcoming PowerShell in Depth book.