I have Forms processes that call workflows using workflow service tasks. When I open one of these processes in the designer, then click on the checkmark to "Validate" the process, I get an error on each of these service tasks. The message says, "The workflow for the service task named "<workflow name>" returned the following error message: 'The remote server returned an error: (404) Not Found.'" 

These workflows seem to run fine, but I'm not able to get them to pass validation. Any ideas?