Symptoms

Normally K2 smartforms and K2 smartforms control pack do not have to be installed on SharePoint 2010 servers. See below for details how to uninstall them.

 

Diagnoses

K2 SmartForms and Control Pack components do not have to be installed SharePoint servers (FWEs/APP). It is possible to run both K2
Workspace and SmartForms from server(s) other than K2 blackpearl server and then this server had to have SmartForms components installed, but in your case you have it all on one server, and can safely remove SmartForms and Control Pack from SharePoint servers.

Having both SmartForms and K2 blackpearl on the same server has an added benefit, because in a such scenario there is no network related latency in communication between two these components.

Essentially on your SharePoint servers you need to run (in the order specified below)
1) K2 smartforms Control Pack Setup Manager and select Remove K2 smartforms Control Pack
2) K2 smartforms Setup Manager and select Remove K2 SmartForms
Related KB: http://help.k2.com/onlinehelp/k2smartforms/userguide/current/default.htm_SF_Remove.html
 

Resolution

See Diagnosis section.