Hey guys, this is my first post here, so please excuse my n00b questions, but I have a problem and maybe you can help?

So, I have OS 10.6.7, and I am having random log-out events. Basically, I am in the middle of doing something (anything - loading program, etc) and I get the beachball, then get dumped back to the log-in screen. I checked the logs in console and it says - (this the most relevant stuff from what I can tell, but i'm no programmer)

BEGIN LOG SEGMENT

Jun 20 18:33:50 William-Littlers-MacBook-Pro LKDCHelper[302]: Starting (uid=501)
Jun 20 18:33:52 William-Littlers-MacBook-Pro Mail[297]: EWSServerVersion: 14.1.225.56
Jun 20 18:34:25 William-Littlers-MacBook-Pro mdworker[295]: CFPropertyListCreateFromXMLData(): Old-style plist parser: missing semicolon in dictionary.
Jun 20 18:37:15 William-Littlers-MacBook-Pro Microsoft Excel[299]: doClip: empty path.
Jun 20 18:37:15: --- last message repeated 3 times ---
Jun 20 18:37:15 William-Littlers-MacBook-Pro [0x0-0x25025].com.microsoft.Excel[299]: Mon Jun 20 18:37:15 William-Littlers-MacBook-Pro.local Microsoft Excel[299] <Error>: doClip: empty path.
Jun 20 18:37:19: --- last message repeated 3 times ---
Jun 20 18:37:19 William-Littlers-MacBook-Pro /usr/libexec/hidd[49]: IOHIDEventQueueEnqueue: Error enqueuing memory. (0xe00002e8)
Jun 20 18:37:26: --- last message repeated 418 times ---
Jun 20 18:37:26 William-Littlers-MacBook-Pro Mail[297]: HIToolbox: received notification of WindowServer event port death.
Jun 20 18:37:26 William-Littlers-MacBook-Pro /usr/libexec/hidd[49]: IOHIDEventQueueEnqueue: Error enqueuing memory. (0xe00002e8)
Jun 20 18:37:26 William-Littlers-MacBook-Pro com.apple.launchd[1] (com.apple.WindowServer[81]): Job appears to have crashed: Segmentation fault
Jun 20 18:37:26 William-Littlers-MacBook-Pro imagent[143]: Quit - notifying about shutdown
Jun 20 18:37:26 William-Littlers-MacBook-Pro imagent[143]: Quit - shutting down daemon
Jun 20 18:37:26 William-Littlers-MacBook-Pro imagent[143]: [Warning] imagent shutting down
Jun 20 18:37:26 William-Littlers-MacBook-Pro PdaNetMac[167]: HIToolbox: received notification of WindowServer event port death.
Jun 20 18:37:26 William-Littlers-MacBook-Pro PdaNetMac[167]: port matched the WindowServer port created in BindCGSToRunLoop
Jun 20 18:37:26 William-Littlers-MacBook-Pro com.apple.launchd.peruser.501[116] (com.apple.Dock.agent[120]): Exited with exit code: 1
Jun 20 18:37:26 William-Littlers-MacBook-Pro imagent[143]: Unable to create APS daemon connection: (ipc/mig) server died
Jun 20 18:37:26 William-Littlers-MacBook-Pro imagent[143]: Unable to set enabled topics: (ipc/send) invalid destination port
Jun 20 18:37:26 William-Littlers-MacBook-Pro /System/Library/CoreServices/loginwindow.app/Contents/MacOS/loginwindow[311]: Login Window Application Started
Jun 20 18:37:26 William-Littlers-MacBook-Pro com.apple.ReportCrash.Root[310]: 2011-06-20 18:37:26.739 ReportCrash[310:1407] Saved crash report for WindowServer[81] version ??? (???) to /Library/Logs/DiagnosticReports/WindowServer_2011-06-20-183726_localhost.crash
Jun 20 18:37:27 William-Littlers-MacBook-Pro loginwindow[311]: Login Window Started Security Agent
Jun 20 18:37:27 William-Littlers-MacBook-Pro com.apple.WindowServer[313]: Mon Jun 20 18:37:27 William-Littlers-MacBook-Pro.local WindowServer[313] <Error>: kCGErrorFailure: Set a breakpoint @ CGErrorBreakpoint() to catch errors as they are logged.
Jun 20 18:37:27 William-Littlers-MacBook-Pro WindowServer[313]: kCGErrorFailure: Set a breakpoint @ CGErrorBreakpoint() to catch errors as they are logged.
Jun 20 18:37:35 William-Littlers-MacBook-Pro SecurityAgent[322]: NSSecureTextFieldCell detected a field editor ((null)) that is not a NSTextView subclass designed to work with the cell. Ignoring...
Jun 20 18:37:35 William-Littlers-MacBook-Pro loginwindow[311]: Login Window - Returned from Security Agent
Jun 20 18:37:35 William-Littlers-MacBook-Pro loginwindow[311]: USER_PROCESS: 311 console
Jun 20 18:37:35 William-Littlers-MacBook-Pro com.apple.launchctl.Aqua[328]: launchctl: Please convert the following to launchd: /etc/mach_init_per_user.d/com.adobe.SwitchBoard.monitor.plist
Jun 20 18:37:35 William-Littlers-MacBook-Pro com.apple.launchd.peruser.501[116] (com.apple.ReportCrash): Falling back to default Mach exception handler. Could not find: com.apple.ReportCrash.Self
Jun 20 18:37:35 William-Littlers-MacBook-Pro com.apple.launchctl.Aqua[328]: com.apple.FolderActions.folders: Already loaded
Jun 20 18:37:35 William-Littlers-MacBook-Pro com.apple.launchctl.Aqua[328]: com.valvesoftware.steamclean: Already loaded
Jun 20 18:37:36 William-Littlers-MacBook-Pro com.apple.launchd.peruser.501[116] (com.apple.Kerberos.renew.plist[345]): Exited with exit code: 1
Jun 20 18:37:36 William-Littlers-MacBook-Pro apsd-ft[361]: APS daemon launched
Jun 20 18:37:36 William-Littlers-MacBook-Pro apsd-ft[361]: Successfully got client identity
Jun 20 18:37:36 William-Littlers-MacBook-Pro com.apple.launchd.peruser.501[116] (0x100115710.mach_init.switchboard.sh): Failed to check-in!

END LOG SEGMENT

So... this seems to be utterly random. It can happen minutes from first login, or it can happen after i've been logged in for hours.

Any ideas?

Thanks!