Originally Posted by AndyOpie150
Try pulling the battery and then holding down the power button (this is called a soft reset).
If that doesn't work and you are not rooted(this will brick a rooted phone) try going to settings/privacy menu and select the factory reset option (this will wipe all user data from the phone and make it like it was when you first purchased it).
Before you try the factory reset option download App Tyrant from the Market. Open it up. It will automatically backup all you applications in their .apk form to the uSD card. Pull the uSD card out and put it onto a PC and transfer the contents into a new folder. This is just in case (happened to me once) it messes up your uSD card and you end up having to reformat it to FAT or FAT32.
I would also make a note of where you placed your apps on each page so you don't end up scratching you head too much when you go to install them from App Tyrant once you have downloaded it after the factory reset.
Okay, I pulled out the battery and did what you told me to do but when I turned on the cell phone and tried to open the camera it gave me the same error message as before. I also followed your steps on resetting my phone but unfortunately it gave me the same outcome as before.