Thanks for your quick response. I have created a variable called docs of type Document But where should I mention the document which need to be attached. In attachment(variable) I selected variable from drop down and gave docs there. But I get the same error.
Also in administration console do we have to add the email endpoints?what I see now is EJB,SOAP,Remoting and taskmanager. when do we add the Email endpoint?
If you use the Send Email with Attachment, just put the name you want for the attachment under 'Attachment Name' and the name of the variable that contains the content under 'Attachment'.
Before that email step, you'll need to make sure the document variable is loaded with the content you want, and how to do that depends where the content is located. If it's in a variable, you can use the SetValue, if it's on the file system, you can use ReadDocument, etc.