I'm guessing that until the lawsuit is settled that any filming will stop so as not to compromise the suit and increase their liability.
You can read about the lawsuit here.
Season One air dates were:
Episode 1: Rockingham 5/14/2004
Episode 2: Las Vegas 5/21/2004
Episode 3: Atlanta 5/28/2004
Episode 4: Darlington 6/4/2004
Episode 5: Bristol 6/11/2004
Episode 6: Dallas 6/18/2004
Episode 7: Martinsville 6/25/2004
Episode 8: Daytona 7/2/2004
Season Two air dates were:
Episode 1: Daytona 5/13/2005
Episode 2: California 5/20/2005
Episode 3: Las Vegas 5/27/2005
Episode 4: Atlanta 6/3/2005
Episode 5: Bristol 6/10/2005
Episode 6: Martinsville 6/17/2005
Episode 7: Texas 6/24/2005
Special: Robby Gordon 7/1/2005
The lawsuit was filed in October. Also, if you have a subscription to
www.tv.org you can download any episodes you may have missed.