Got an e-mail from T-Mobile's BlackBerry Tech Support regarding to solve error problems such as App Error 523. Certainly look like we really don't need to use JL_Cmder program. Here is an instruction from T-Mobile BB Tech Support.
The operating system on the device has become corrupted. Please reinstall the handheld software for the BlackBerry Device using the Blackberry Desktop Manager and current Handheld Software.
Before proceeding, make sure that the latest BlackBerry Desktop Software is installed on the computer by completing the following steps:
If you do not have the Blackberry Desktop Software, visit this link: How to upgrade to the latest software version - RIM Blackberry All Models
Warning: The following procedure will erase all data from the BlackBerry device. Back up the BlackBerry device before proceeding. For instructions, see KB12487 (BlackBerry Search Results
To perform a clean install of the BlackBerry Device Software, perform the following steps:
1. Connect the BlackBerry device to the computer and open BlackBerry Desktop Manager. (my advise is to remove a battery first and do not reinsert yet)
2. Double-click the Application Loader icon.
3. Click Next to start the installation process.
4. Type your BlackBerry device password, if prompted, and click OK.
5. Click the check boxes next to the names of the applications you want to load and click Next.
6. Click Advanced, and then click the check box beside Erase all currently installed applications. (put a battery on)
7. Click Next.
8. Click the check box next to Do not automatically backup the application data during the loading process, and uncheck the box next to Backup and restore applications installed wirelessly.
9. Click Next > Finish.
10. When the process has completed, the message The loading operation was successful will appear. Click Close to return to BlackBerry Desktop Manager.