mount knoppix-data.img as ext3

I am using knoppix 6.0.1 but I have upgraded the kernel to new kernel ( 2.6.31.5 )
and using aufs2. But most of the scripts in the system is still based on knoppix 6.0.1.
Most notably I noticed that knoppix would mount knoppix-data.img by specifying it
as ext2 file system. I wonder why it is not mounted as ext3 file system, as it seems,
everytime the system reboot, it spends significant time doing file system check.

I did a try on mounting it as ext3 file system but I noticed that it will hang.
Perhaps aufs(2) will not work together with ext3 file system ?
( I get hang boot up too with mounting knoppix-data.img as ext2, but it's
a lot less frequent - anyone has encountered the same thing as me ? )

Appreciate input.