error : Output could not be issued

Dear Expert,

I am not able to take print out of one of my invoice. While looking for print preview i am getting error message as below :

Output could not be issued

Message no. VF 304

Diagnosis

An error occurred while output was being issued. It is possible, for example, that the form to be issued has not been activated or has an error. An error may also have arisen while the data to be issued was being edited.

I did some changes in smartform but all is activated and other invoices are showing proper output except one.

can you please tell me possible causes to trace this error.

Thanks.