IChat Does Not Activate iMac's Camera and Behaving Strangely

Question

Hello,
I opened up iChat this morning in an effort to place a video call with my father across the country. We've done this plenty of times without issue. We both own new 27" iMacs with built in iSight cameras and have fast internet connections. All software and the OS is up to date. Today, however, we could not connect and it became evident that my iChat application was the cause of the problem. Repeated attempts to initiate video calls resulted in nothing. Clicking on the video chat icon yielded nothing.
When I open up iChat's preferences, nothing happens either. By selecting it a second time, I eventually get the preferences window to open up with a message: "Select a button first!" I can select the General tab, as well as Accounts, Messages, and Alerts. However, when I click on the Audio/Video tab, nothing happens. The application behaves like I didn't click anything and keeps the previously selected preferences tab active.
To investigate the issue further, I opened up another Apple camera app: Photo Booth. Oddly, Photo Booth immediately crashes. Among other things, the report generated says the following: "Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '+[ compositionWithFile:]: unrecognized selector sent to class 0x7fff70d91b08'"
When I open up Skype, the camera is recognized and powered on (green LED turns on) and I can have video conversations. Skype works great. So it appears Apple based applications utilizing the built in camera are having issues. Actually, I just tested video recording within Quicktime Player without issue.
Does anyone know what I can do to resolve this? I realize my father and I can use Skype to make our video call, but it's the screen sharing functionality built into iChat that we need to use. And for whatever reason, this functionality also does not work within iChat. Selecting the option "Share screen with..." results in nothing- as if I didn't select it. It's very frustrating not to all least get an error.
Any feedback is much appreciated. Thank you!

Answer 1

Hi,
That is a different one.
Never seen or heard of that.
Summary so I can list what I understand.
Clicking your Own video icon next to your Buddy pic show nothing.
The Audio/Video section of the iChat Preferences is not available.
Clicking a Buddy's Video icon also produces nothing.
Can you say where you saw this ?
"Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '+: unrecognized selector sent to class 0x7fff70d91b08'"
Was it in Console and did it have any info on what app or framework was involved ?
This would seem to implicate the com.apple.ichat.plist
(there used to be an Error that would stop the Preferences appearing at all - related to the fact iChat windows never have the top right oblong white Hide/Reveal Tool Bar option button).
However iChat also has a "Software camera" as it is called that does the bit about doing the Screen Sharing.
iChat also uses two files (in this case) about Video production.
One I am sure about (a USB digitiser) and a second (ApplePixelSomething) that I am not so sure about.
I believe the first makes a UVC complaint camera look like a DV input to iChat and Photo Booth.
If you are at 10.6.6 this run this Combo Version of the Installer over the tops of what you have.
The 10.6.7 one is here
Hopefully this will correct any faults with these files (If they have been updated since the OS came out).
You could try deleting com.apple.ichat.plist
This is found in your Home Folder/Library/Preferences
Drag it to the Trash and restart iChat if open.
This will recreate the .plist from default held in the iChat app.
It does remove all the settings you have made in the iChat Preferences:-
Font
Font Colour
Background to IM colour
Saved Transcripts
and so on
9:52 PM Sunday; April 3, 2011
Please, if posting Logs, do not post any Log info after the line "Binary Images for iChat"