Never struck this issue before.
Normally I add a people picker to Infopath 2010 and set the sharepoint site and then move on.
Later, when I am doing a sharepoint workflow I will user a lookup to get current item:field name and then use the "return field as" drop down to select email address.
This means I can then use this in the send email workflow action.
For some reason the dropdown is greyed out in this instance.
I am logging to the wrokflow history to see what the value is and I am getting an empty string.
Any ideas?
Only difference between this form and previous ones is that this form is being published as a content type rather than a default form to a library. No idea if that makes a difference.