App Error 523, is an application error that appears on most models of smartphone-uri BlackBerry. Of the BlackBerry Pearl, until BlackBerry Storm, Curve and Bold, this error It sometimes makes its presence felt. The error appears behind installation of applications, and the strong phase is like the error does not disappear by simple uninstallation of the application considered suspected of App Error 523.
Solving the Error 523 App Error can be done in two ways:
1. Reset Complete a deviceto (to return to the manufacturing settings), which involves uninstalling the operating system (OS) and losing all data. Of course, before starting this operation is recommend you a flall-back via BlackBerry Desktop Manager.
2. In most cases the error is given by the module net_rim_bb_mms. The best solution would be uninstalling this module, and reinstalling “cleanse”.
Okay, let's see how we can do a hard reset of a blackberry device, and how we can delete a module.
How to reset a BlackBerry device (hard reset) – Wipe HandHeld
Most models, less BlackBerry Pearl, have this option of Master Reset (Wipe HandHeld) in Options -> Security Options -> General Settings -> Wipe HandHeld.
For BlackBerry Pearl, you must go in Options -> Security Options -> General Settings And press on the BlackBerry menu key to have access to Wipe Handheld.

This operation can take in some cases and over 2 hours. Connect the device to your PC, turn on BlackBerry Desktop Managers, and Reinstalli-ul.
This would be the first method of uninstall and reinstall BlackBerry OS, but for a healthier Wipe, we recommend you Jl_Cmder.
Jl_cmder is an application created by RIM, very simple, and that allows you to see information about the device, logthe operations (devicelog), do screenshotthe on smartphone, in Delete the operating system (wipe) si sa Reset the device at manufacturing settings (resettofactory).

Download : JL_Cmder (Read the instructions on the download page carefully)
Install os restore ass jl_cmder
1. Open Desktop Manager and select Application Loader
2. Install the OS by following the prompts and selections
3. The device will reboot. It can take up to 15 minutes for the 1st boot.
4. Restore the previously made backup or re-sync
5. Install the battery back into the device and unplug from the PC
Full details, for Wipe by JL_Cmder, you can find them on the Rim page. Wipe The Device.
After the reinstruction of the OS, the error App Error 523 it will disappear.
Another method to get rid of the 523 app, would be to delete the Net_rim_BB_MMS module. You can do this with jl_cmder.
1. Open the JL_CMDER application and press the key 6. (Command-Line Usage)
2. Enter your order line: javaloader -u -w erase -f net_rim_bb_mms
After this operation, everything should go normally.