im having a similar problem .
camera not working
I have cssu testing installed .

no fcam drivers ( had them at some point in time but removed)
1. the camera takes the 1st picture w no problem but when i'm taking sey a second picture , the captured image gets stuck on the screen it stays black and blank sometime . It doesnt render any change even when the capture button is depressed .
moreover my photos don't save to my default camera folder.
there no way of locating my pictures now.

If no solution any tips on downgrading to cssu stable would be nice since thats proving to be a feat as well

Any help would be greatly appreciated.

Yes - uninstall the Blessn900 and other device that use the camera such as the Flashlight.

Reboot, and if it runs, its the lens cover sensor curse.

Install the applications you removed, one at a time. Put it simple, you may have flipped the cover back by accident and back causing the sensor to act as a semaphore/lock. The other applications leave it to the Camera to be "master" of this. A variant this is the quest for "who let go of that smell" - where the first one to respond is assigned the responsibility.

ouch no luck , uninstalled flashlight reboot *2.
help pls!

After many months of successful use of the camera, the camera stopped working. My system is version 21.2011.38-1.002. When I launch the camera (eg. by opening the shutter) I see a black screen instead of a camera image. After 4 seconds a yellow system message "operation failed" appears, and the application closes. During these two seconds I can click on several of the icons. The memory storage location icon reads normally. the "exposures" remaining reads normally: 999. Everything else I looked at looks. OK

I tried
* reboot. No effect.
* removing battery for hours and rebooting. This caused reset of time and date. No effect on camera problem.
* plugging the N900 in to a new Mac (system 10.6.8) in mass storage mode and doing a disk verify. It checked out OK.
* opening camera slide while USB mass storage is connected. During the 4 seconds, the "pictures available" displays shows a red 000. So this behavior is normal.
* invoking dmesg from xterm. I see messages accurately reporting camera slide being opened and shut.
* invoking "App. manager" and requesting updates. It says no updates are available.
* checking many forums and bug reports. No one reports a hardware failure of the camera module.
* invoking "camera-ui" from xterm. I get the command prompt again after 4 seconds. This happens whether I have the slide open or shut before or after invoking the command.

My software.
* no software installed in many months
* I have installed flashlight (it still works fine), vim, freecell, gnuplot, commercial word-to-go package downloaded from Maemo site.

My guess is that I have a hardware failure of the camera module. Is this likely or unlikely?
Is there a way I can test for this? Is there a way to query the camera module?

Thanks for your thoughts! TW

You can use gstreamer for testing the camera:

install gstreamer-tools
run
gst-launch v4l2src ! xvimagesink
(it should open a window showing the camera output)