It appears to be downloading he defs now, but is unable to process them as below:
6/26/2014, 9:25:59 GMT -> Progress Update: PATCH_START: Patch File: "C:\ProgramData\Symantec\LiveUpdate\Downloads\Updt598\1403758927jtun_sep12enncur26.m26", Script File: "C:\ProgramData\Symantec\LiveUpdate\Downloads\Updt598\SP12v32f.dis"
6/26/2014, 9:25:59 GMT -> Progress Update: SECURITY_PACKAGE_TRUSTED: "C:\ProgramData\Symantec\LiveUpdate\Downloads\Updt598\1403758927jtun_sep12enncur26.m26"
6/26/2014, 9:25:59 GMT -> Signer: cn=Symantec Corporation,ou=Locality - Culver City,ou=Product Group - LiveUpdate,ou=SymSignature 2005,o=Symantec Corporation
6/26/2014, 9:25:59 GMT -> Progress Update: UNZIP_FILE_START: Zip File: "C:\ProgramData\Symantec\LiveUpdate\Downloads\Updt598\1403758927jtun_sep12enncur26.m26", Dest Folder: "C:\ProgramData\Symantec\LiveUpdate\Downloads\Updt598"
6/26/2014, 9:26:00 GMT -> Progress Update: UNZIP_FILE_FINISH: Zip File: "C:\ProgramData\Symantec\LiveUpdate\Downloads\Updt598\1403758927jtun_sep12enncur26.m26", Dest Folder: "C:\ProgramData\Symantec\LiveUpdate\Downloads\Updt598", HR: 0x0
6/26/2014, 9:26:00 GMT -> Added package to cache...
6/26/2014, 9:26:00 GMT -> LiveUpdate couldn't expand replacement path [spcVirDef32InstallDir].
6/26/2014, 9:26:00 GMT -> Progress Update: PATCH_ERROR: Patch File: "C:\ProgramData\Symantec\LiveUpdate\Downloads\Updt598\1403758927jtun_sep12enncur26.m26", Script File: "C:\ProgramData\Symantec\LiveUpdate\Downloads\Updt598\SP12v32f.dis", HR: 0x802A0006
6/26/2014, 9:26:00 GMT -> HR 0x802A0006 DECODE: E_DIS_SCRIPT_SYNTAX_ERROR
6/26/2014, 9:26:00 GMT -> Progress Update: PATCH_FINISH: Patch File: "C:\ProgramData\Symantec\LiveUpdate\Downloads\Updt598\1403758927jtun_sep12enncur26.m26", Script File: "C:\ProgramData\Symantec\LiveUpdate\Downloads\Updt598\SP12v32f.dis", HR: 0x802A0006
6/26/2014, 9:26:00 GMT -> HR 0x802A0006 DECODE: E_DIS_SCRIPT_SYNTAX_ERROR
6/26/2014, 9:26:00 GMT -> EVENT - PRODUCT UPDATE FAILED EVENT - Update available for SEPM Virus Definitions Win32 v12.1 - MicroDefsB.CurDefs - SymAllLanguages. Update for CurDefs takes product from update 0 to 140625032. Server name - liveupdate.symantecliveupdate.com, Update file - 1403758927jtun_sep12enncur26.m26, Signer - cn=Symantec Corporation,ou=Locality - Culver City,ou=Product Group - LiveUpdate,ou=SymSignature 2005,o=Symantec Corporation, package install code 0. The Update executed with a result code of 1825, => The install script for this product had a syntax error, so LiveUpdate could not install it.
Out of curiosity, can you post the sesmlu.log as well?