Go back to the IRCTC site and Log in again and retrieve your booked ticket section. View the ticket again on the web and take a print out or save as pdf file. Mostly, you will not have this defect. This may be bcoz of some error in uploading the e-ticket on the system.
However if error still remains, then try helpline number or send email to IRCTC. They are very quick in responding.
Just try out and update here.