Generate document is not working

epayment

Am using the BIRT -report designer to design reports .
WHen i click on View--> Run report --> Web Viewer the report executes perfectly .

When i click on View-->Generate document
it asks me whether to save the document and then i click Yes and it asks me to OPen the folder and I open the folder and there is no .design file

It used to work perfectly and stopped all of a sudden.
Any help much appreciated