Looks like the AV component can not be installed.
Thu, 20 Aug 2015 11:43:24 INI: EXEC04=C:\Program Files (x86)\LANDesk\LDClient\vulscan.exe, /installKavClient /removeOldAV /noupdate /nosync /ob:RebootBehavior=LANDESKCORE_v327 /KLBehavior=LANDESKCORE_v348 /rebootaction=never /showui=false, INSTALLONLY
Thu, 20 Aug 2015 11:43:24 Starting process: C:\Program Files (x86)\LANDesk\LDClient\vulscan.exe /installKavClient /removeOldAV /noupdate /nosync /ob:RebootBehavior=LANDESKCORE_v327 /KLBehavior=LANDESKCORE_v348 /rebootaction=never /showui=false
Thu, 20 Aug 2015 11:43:28 Processes returned : -1917648418
Thu, 20 Aug 2015 11:43:28 FAILED: Unable to install LANDesk Antivirus. LANDesk Antivirus install status listed at Security and Compliance | Security activity | LANDesk Antivirus | Recent activity. Please create and run an 'Install/Update security components' task from the Agent Settings tool with the option 'Troubleshoot LANDesk Antivirus installation using interactive mode' (or from the commandline run: vulscan.exe /installav /interactive). This will run the setup with UI and show which software is incompatible.
Thu, 20 Aug 2015 11:43:28 FAILED: Running application: C:\Program Files (x86)\LANDesk\LDClient\vulscan.exe /installKavClient /removeOldAV /noupdate /nosync /ob:RebootBehavior=LANDESKCORE_v327 /KLBehavior=LANDESKCORE_v348 /rebootaction=never /showui=false
Thu, 20 Aug 2015 11:43:28 FAILED: bCriticalError set to TRUE. Processing C:\Program Files (x86)\LANDesk\LDClient\vulscan.exe
As written in the logfile, for further investigation I would try to install the landesk agent without the AV component. And afterwards try to deploy the AV component over an "install/update security components" task, with all progress diaglogs and interactive troubleshooting on.
May this will give you more details whats going wrong here