Description of the problem:

Running M2K workflow with invalid values doesn't provide a informative error message to the user.

How reproducible:

100%

Steps to reproduce:

1. deploy Orchestrator 0.2.3

2. Deploy workflows

3. Run M2K workflow with dummy values

Actual results:

Error message doesn't tell the user anything about what went wrong 

Expected results:

Clear error message that tells the user something informative about what is happening