This has to do with the built-in check the Agent performs. If the Agent can't perform the check it will keep on running the installation.
- From the Manager console double click on the affected Installation Item
- Go to the Deployment Options tab
- Delete the Check value or enter a valid Check value
As of version 5.2 a time-out has been added which is set to 120 minutes by default. You can edit the default time-out by doing the following:
- From the Manager console double click on the desired Installation Item
- On the Installations tab there is now a Time-out (minutes) option in which you can select the desired minutes by pressing the up or down arrows or typing the desired time-out.