When opening K2 Package and Deployment using MMC the following error is displayed:
"MMC could not create the snap-in"
The error is caused by some referenced assemblies not being loaded correctly.
Open the K2 Blackpearl Installer from the Install media (referred to the location where you downloaded and extracted the EXE).
If you do not have the K2 Blackpearl installer from the install media anymore, download a new copy from the portal site. Remember to download the same version as the version you are already running.
Select to run a Repair. This should resolve the issue.
More information regarding reparing a K2 Installation can be found in the K2 Installation and Configuration Guide: