Danny,
CCSv6.0 Beta 4 is version 6.0.0.00156, which you need for Flash Programming on TMS320F2837x devices. Unfortunately, we do not support updating from beta 3 to beta 4, so you will need to download it again from the following site:
http://processors.wiki.ti.com/index.php/CCSv6#Downloads_.28Beta_4.29.C2.A0
Do note that the full version of CCSv6.0 is scheduled to be released soon (I don't have the exact date), so if you do not want to download CCS again once it is released, you can wait a week or two. Otherwise, please download beta4 and let me know if you have any problems with Flash Programming on the TMS320F2837x device.
Thanks,
Ricky