I can't tell if this is an answer to another question, or a question in it's own right.
Assuming the second, then the answer is that your workflow allows you to select any date fields to work with. It does NOT know if the field you pick is valid for the project/issue-type that the workflow will eventually be used with. In other words, it lets you configure a duff transition, and then falls over when you execute it. Check that the field configuration and context in the target project allow "customfield 10511" for that project/issuetype
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.