Matt,
I don't think I'm following you here. You're using XDS100v2 emulator. If you launch this target config in the target config view, you can connect to your F28335 and everything is fine, correct? But if you right-click the project and select Debug_As->1_Code_Composer_Debug_Session, you're saying you get the error you cited?
What happens if you click the green "Debug" icon in the 'CCS Edit' view (I'm assuming you're asking about CCSv5)?
Also, what version of CCS are you using?
Regards,
David