Gather Inventory Task Failure

I am having issues with some clients not checking in for inventory, so I created a new gather inventory task, the task fails on some with the following error message, The agent for this task type in not installed, seems like I am missing the inventory agent, my question is is my Symantec management agent corrupt or should I manually install the inventory agent, where can I find a new symantec manangement agent at?? Thanks in advance for your help.