error #9 when export to IGS file(for railworks)

Hi everyone, I just buyed a few times ago 3Dcrafter because I do routes for trainz and railworks, but I do the design in Sketchup, and I use 3Dcrafter to convert for railworks, but often I get the error that I put on topic and the software crash, so I can not continue.

My config, is win 7 home premium 4GB for RAM, 2,1GHZ dual core for CPU

How can I work in the right condition ?

Thanks for your help and answer

There are several topic about exporting from SU to 3DC at RailworksAmerica.com; however I would highly recommend that you learn to use 3DC, and not use SU. It will save you some headache, and having to do steps twice.

If you need specific information about creating models for railworks you may be interested in my blog:
http://thegradecrossing.blogspot.com/2013/02/3dc-to-railworks-table-of-contents.html