The environment variable FOP_OPTS is not used by the batch files
fop.bat and fop.cmd
In compliance to fop.sh I changed fop.bat AND fop.cmd.
Both fixes were successfully tested with the current source
version based on SVN from date 20080918 and also tested with the
current stable version 0.95.
You can reproduce the bug with any huge .xsl-fo file or .fo file starting FOP under Windows with fop.bat.
The patch is attached.