You might encounter an error while trying to publish workflows with an 'Email Step' added
Error : "An error occured when the workflow was being created. Try to save the workflow again."

The crm logs shows the error as
"Type System.Globalization.CultureInfo is not marked as safe ... in web.config"

Here is the resolution

Add the below entry into the web.config file available in the crm installation directory
Eg : c:\program files\microsoft dynamics crm\crmweb


Try publishing the workflow again. That should work :-) !!