Endpoint Protection

I am trying to install SAV 10.1.9 client on a Windows 2003 Enterprise 64-bit machine. The server previously had version 10.1.7 installed.
The install runs to the very end and then suddenly rolls back with the message "The wizard was interrupted before SAV Win64 could be installed completely. Your system has not been modified. To complete installation at another time, please run setup again. Click Finish to exit the wizard."

On one particular install attempt I was even able to open the SAV application right after the install but then it dissapeared soon after!!

I have tried running NoNAV.exe on the server to remove the old version and doing a clean install but I get the same result.
The 10.1.9 install runs perfectly on our 32-bit servers.

I have attached the MSI install logs from the failed installation, one is detailed, one more basic.

Can anyone figure out why this is happening or come across similar???

From the log

Info 1903.Scheduling reboot operation: Deleting file C:\Program Files (x86)\Common Files\Symantec Shared\TBD1E3.tmp. Must reboot to complete operation.
Info 1903.Scheduling reboot operation: Deleting file C:\Program Files (x86)\Common Files\Symantec Shared\TBD1E4.tmp. Must reboot to complete operation.
WriteCcSettingsTables: StopCcSetMgrOnOverOrBrokenInstall.D3A883B9_8F94_4E7D_96B6_852388CE5647
WriteCcSettingsTables: StopCcSetMgrOnOverOrBrokenInstall_R.D3A883B9_8F94_4E7D_96B6_852388CE5647
MSIASSERT - StopCcSetMgrOnOverOrBrokenInstall_Rol:  Could not open key. Error:2: 
WriteCcSettingsTables: Creating folders
WriteCcSettingsTables: Removing system registry values
WriteCcSettingsTables: Removing ODBC components
WriteCcSettingsTables: Deleting services
WriteCcSettingsTables: Stopping services
WriteCcSettingsTables: DeleteCcSettingsTables.03FE01CF_295E_4354_A292_7DC4A810E0DA
WriteCcSettingsTables: DeleteCcSettingsTables_Rol.03FE01CF_295E_4354_A292_7DC4A810E0DA
Action 11:06:48: WriteCcSettingsTables. Configuring settings.  This may take several minutes.
MSIRESULT PASS - MsiHelper::CMsiDefRegArchive::Init: Start Initialization: 
MSIRESULT PASS - MsiHelper::CMsiDefRegArchive::Init: Getting custom action data: 
MSIRESULT PASS - MsiHelper::CMsiDefRegArchive::Init: szFileName == '': 
MSIRESULT PASS - WriteCcSettingsTables: End WriteCcSettingsTables: 
WriteCcSettingsTables: Updating component registration
WriteCcSettingsTables: SetOneTimeUpdateCookie_RB.93C43188_D2F5_461E_B42B_C3A2A318345C
Action ended 11:06:48: INSTALL. Return value 3.

can you reboot the machines and try installing it; check the manual uninstall document too and install fresh.
http://service1.symantec.com/SUPPORT/ent-security.nsf/docid/2005050210381448

I've rebooted the server.

Next I ran throught the manual uninstall instructions for 10.1 http://service1.symantec.com/SUPPORT/ent-security.nsf/docid/2006022212084148 (rather than the 10.0 instructions you suggested. I also deleted any other reference to Symantec in the registery as there were a couple of others.
Rebooted again and same issue.

I've attached the latest log file which is slightly different...