Share my experience about 2 versions: K2.Net 2003 and K2 BlackPearl,
A long time, i installed K2.Net 2003 and working with it, when K2 BlackPearl launching. I installed K2 BlackPearl, but i don't want uninstall K2.Net 2003. So, working with K2 BlackPearl appear many errors that i can't control or config 2 platforms (such as: One of these are Workflow Design can not Update). Finally, uninstall K2.Net 2003, everything OK.
I hope no one have the same problem.
Regards,