Add me to the list of very frustrated victims on this issue. One day I'm deploying InfoPath integrated process no problem. The next day I get the same errors reported here no matter what I try. I will open a support ticket too and point them here, but in case anyone else is thinking about trying different workarounds, here are all the things that did NOT work for me:

1. I was already one of the site collection administrators
   
2.  Adding myself to the Farm Administrators group and running IISReset
3. Changing the form mode from "InfoPath" to "Web Browser" and back (which apparently did work for some here, but not me)
4. Deleting the culprit .msbuild file to force K2 to generate from scratch
5. Deployed while running the K2 Server in Console Mode (no errors show in the console)
6. Many possible configurations of the InfoPath integration including pulling the form in from SharePoint, Local Drive, and many other combinations of wizard settings
7. Completely deleting old process using dbo.wProcDelete, rebooting all servers / clients, and starting a new project from scratch
8. Ran VS.Net as domain\administrator to see if I could get another user to successfully deploy even though my user is already a member of Domain Admins
   

Other Notes:

1. I am running the latest 0803 release of Blackpearl
2. Removing the InfoPath integration from the process I am able to deploy without any problems. Re-adding InfoPath integration it fails.
   
   

Anyone tried / figured out any other workarounds to this? Any word back from Support on those tickets already submitted?