Application Switcher Errors Reported in Console

Greetings, folks!

When the cmd-tab keys are pressed, Console immediately reports a string of Dock errors. No other errors are reported after the initial press, regardless of subsequent input (h, q, tab, tilde).

Removing the ~/Library/Preferences/com.apple.dock.plist and logging out/in made no difference. Thoughts? Thanks!!

#### initial errors after login ####

2011.8.28 9:33:45PM com.apple.Dock.agent[31059] Sun Aug 28 21:33:45 HD.local Dock[31059] <Error>: kCGErrorIllegalArgument: CGSCopyWindowProperty: Invalid (NULL) window

2011.8.28 9:33:45PM com.apple.Dock.agent[31059] Sun Aug 28 21:33:45 HD.local Dock[31059] <Error>: kCGErrorFailure: Set a breakpoint @ CGErrorBreakpoint() to catch errors as they are logged.

2011.8.28 9:33:45PM com.apple.Dock.agent[31059] Sun Aug 28 21:33:45 HD.local Dock[31059] <Error>: kCGErrorIllegalArgument: CGSGetWindowProperty

2011.8.28 9:33:45PM com.apple.Dock.agent[31059] Sun Aug 28 21:33:45 HD.local Dock[31059] <Error>: kCGErrorIllegalArgument: CGSCopyWindowProperty: Invalid (NULL) window

2011.8.28 9:33:45PM com.apple.Dock.agent[31059] Sun Aug 28 21:33:45 HD.local Dock[31059] <Error>: kCGErrorIllegalArgument: CGSGetWindowProperty

2011.8.28 9:33:45PM com.apple.Dock.agent[31059] Sun Aug 28 21:33:45 HD.local Dock[31059] <Error>: kCGErrorIllegalArgument: _CGSFindSharedWindow: WID 59

2011.8.28 9:33:45PM com.apple.Dock.agent[31059] Sun Aug 28 21:33:45 HD.local Dock[31059] <Error>: kCGErrorIllegalArgument: CGSCopyWindowProperty

2011.8.28 9:33:45PM com.apple.Dock.agent[31059] Sun Aug 28 21:33:45 HD.local Dock[31059] <Error>: kCGErrorIllegalArgument: CGSGetWindowProperty

#### common subsequent errors ####

2011.8.28 9:33:58PM com.apple.Dock.agent[31059] Sun Aug 28 21:33:58 HD.local Dock[31059] <Error>: kCGErrorIllegalArgument: CGSCopyWindowProperty: Invalid (NULL) window

2011.8.28 9:33:58PM com.apple.Dock.agent[31059] Sun Aug 28 21:33:58 HD.local Dock[31059] <Error>: kCGErrorIllegalArgument: CGSGetWindowProperty

2011.8.28 9:33:58PM com.apple.Dock.agent[31059] Sun Aug 28 21:33:58 HD.local Dock[31059] <Error>: kCGErrorIllegalArgument: CGSCopyWindowProperty: Invalid (NULL) window

2011.8.28 9:33:58PM com.apple.Dock.agent[31059] Sun Aug 28 21:33:58 HD.local Dock[31059] <Error>: kCGErrorIllegalArgument: CGSGetWindowProperty

2011.8.28 9:33:58PM com.apple.Dock.agent[31059] Sun Aug 28 21:33:58 HD.local Dock[31059] <Error>: kCGErrorIllegalArgument: _CGSFindSharedWindow: WID 6593927

2011.8.28 9:33:58PM com.apple.Dock.agent[31059] Sun Aug 28 21:33:58 HD.local Dock[31059] <Error>: kCGErrorIllegalArgument: CGSCopyWindowProperty

2011.8.28 9:33:58PM com.apple.Dock.agent[31059] Sun Aug 28 21:33:58 HD.local Dock[31059] <Error>: kCGErrorIllegalArgument: CGSGetWindowProperty