I got the very same error. Yesterday I updated from Win 8 Pro to win 8.1 Pro. Since then, I cannot install any updates.
2013-10-19 10:33:22:387 480 1250 Service ** START ** Service: Service startup
2013-10-19 10:33:22:387 480 1250 Service *********
2013-10-19 10:33:22:387 480 1250 Agent * WU client version 7.9.9600.16403
2013-10-19 10:33:22:387 480 1250 Agent * Base directory: C:\WINDOWS\SoftwareDistribution
2013-10-19 10:33:22:387 480 1250 Agent * Access type: No proxy
2013-10-19 10:33:22:387 480 1250 Service UpdateNetworkState Ipv6, cNetworkInterfaces = 4.
2013-10-19 10:33:22:387 480 1250 Service UpdateNetworkState Ipv4, cNetworkInterfaces = 3.
2013-10-19 10:33:22:387 480 1250 Agent * Network state: Connected
2013-10-19 10:33:22:387 480 1250 Service UpdateNetworkState Ipv6, cNetworkInterfaces = 4.
2013-10-19 10:33:22:387 480 1250 Service UpdateNetworkState Ipv4, cNetworkInterfaces = 3.
2013-10-19 10:33:22:403 480 1250 Agent *********** Agent: Initializing global settings cache ***********
2013-10-19 10:33:22:403 480 1250 Agent * Endpoint Provider: 00000000-0000-0000-0000-000000000000
2013-10-19 10:33:22:403 480 1250 Agent * WSUS server: <NULL>
2013-10-19 10:33:22:403 480 1250 Agent * WSUS status server: <NULL>
2013-10-19 10:33:22:403 480 1250 Agent * Target group: (Unassigned Computers)
2013-10-19 10:33:22:403 480 1250 Agent * Windows Update access disabled: No
2013-10-19 10:33:22:419 480 1250 WuTask WuTaskManager delay initialize completed successfully..
2013-10-19 10:33:22:419 480 1250 Report WARNING: Failed to initialize event uploader for new server {117CAB2D-82B1-4B5A-A08C-4D62DBEE7782} with hr = 8024043d.
2013-10-19 10:33:22:419 480 1250 Report WARNING: CSerializationHelper:: InitSerialize failed : 0x80070002
2013-10-19 10:33:22:419 480 1250 Report CWERReporter::Init succeeded
2013-10-19 10:33:22:419 480 1250 Agent *********** Agent: Initializing Windows Update Agent ***********
2013-10-19 10:33:22:419 480 1250 DnldMgr Download manager restoring 0 downloads
2013-10-19 10:33:22:419 480 1250 AU ########### AU: Initializing Automatic Updates ###########
2013-10-19 10:33:22:419 480 1250 AU Additional Service {117CAB2D-82B1-4B5A-A08C-4D62DBEE7782} with Approval type {Scheduled} added to AU services list
2013-10-19 10:33:22:419 480 1250 AU AIR Mode is disabled
2013-10-19 10:33:22:419 480 1250 AU # Approval type: Scheduled (User preference)
2013-10-19 10:33:22:419 480 1250 AU # Auto-install minor updates: Yes (User preference)
2013-10-19 10:33:22:419 480 1250 AU # ServiceTypeDefault: Service 117CAB2D-82B1-4B5A-A08C-4D62DBEE7782 Approval type: (Scheduled)
2013-10-19 10:33:22:419 480 1250 AU # Will interact with non-admins (Non-admins are elevated (User preference))
2013-10-19 10:33:22:419 480 1250 AU WARNING: Failed to get Wu Exemption info from NLM, assuming not exempt, error = 0x80070490
2013-10-19 10:33:22:434 480 1250 AU AU finished delayed initialization
2013-10-19 10:33:22:434 480 1250 AU OOBE is in progress, so cannot perform Accelerated Install
2013-10-19 10:33:22:434 480 db0 IdleTmr Incremented idle timer priority operation counter to 1
2013-10-19 10:33:22:434 480 17ac DnldMgr Asking handlers to reconcile their sandboxes
2013-10-19 10:33:23:122 480 1250 AU ########### AU: Uninitializing Automatic Updates ###########
2013-10-19 10:33:23:122 480 1250 WuTask Uninit WU Task Manager
2013-10-19 10:33:23:528 480 1250 Service *********
2013-10-19 10:33:23:528 480 1250 Service ** END ** Service: Service exit [Exit code = 0x240001]
2013-10-19 10:33:23:528 480 1250 Service *************