quick time export

I am exporting a quick time file from my CS 6 time line.

It is a straight time w/o any effects.

So it goes it up till 98% of the render and it comes up with "Unknow Error" message.

I have looked around the forums for this error message but haven't fixed my issue

Here's my setting

Format Quicktime, code H.264, Data rate of 47mbps (limit), encoding quality at 98% and turned on "Use Maximum Render Quality"

It gives the "unknown error" when exporting the tail credits.

So reduced the work area just to the tail end of the movie where it crashed and exported the tail credits and it worked fine.

So my question  - Can cs6 write files of 20 GB ? I have 8GB of RAM Windows 7 machine .

I assigned 5GB of RAM for cs6 premier.

thanks