Wow that is a lot of crashes. From your SS it looks like policies are crashing also. Does the agent work for you?
Can you describe more specifically when the mac is slowing down? For example as soon as you install the LANDesk agent?
Also looking at your crash logs it seems like there is something it doesn't like in your settings file. Maybe bad server address? If you want to attach your /Library/Preferences/com.landesk.ldms.plist file I'll take a look.
The mac will start creeping along, showing the "beach ball" of death.... opening applications up slowly, browsing the internet at a snails pace, then the Finder may become unresponsive.Looking at the logs I find Landesk crashing like crazy so I remove the agent, (remove it manually sometimes ), After removal the Mac no longer has the above issues.
This minimally happens on 1-2 year old macs, Snow Leopard - Lion. It does not always happen.
Plist attached, as well as logs from another mac that is also exhibiting the same problems.
I looked at your plsit and crash logs. I think you should open a ticket with support for this issue. Your plist looks good and I have been unable to duplicate the symptoms you are seeing.