Rajesh - obviously we are running out of memory here.
There are 2 possible reasons I can see.
1. We really are out of memory - This could be the case depending on the hardware, process limits and size of the report being created. You should be able to check this from the task manager. Build up the size of the report data until you reach the limit.
2. Something in the layout is causing a repeating loop that never ends and just goes on creating pages for content eventually running out of memory. Remove some rows temporarily from the report (including the one it stops on and see if it succeeds.
We have tested the application on a 600 page document with 10,000 records and it can run up to 0.5Gb data. So it could be that you really are out of memory. It is one of the things we are looking at, and can see a number of ways to reduce the memory footprint in all stages of generation.
You could also merge each table into a single long table and see if that helps (styles and column spans will help match your existing layout).