On my blackberry, I get a "No Additional Applications Designed For Your Device Were Found" error

Reasons you might see that message include:

1) You need to upgrade your version of the RIM Desktop Manager. You can download the latest version of the Desktop Manager here. You may find it necessary to uninstall the previous version and then install the new one (as this has helped a few).

2) You need to install the proper device software for your model BlackBerry to your PC. Please note, I’m not saying that you need to update your device OS. I’m saying you need to download the software that tells the Desktop Manager how to properly talk to your device. RIM has unfortunately named this software the “Device” software, which implies to me that it is something that should go on the handheld, but it actually is installed to your PC. To see which version of the device software you already have installed, go to the About menu on the Desktop Manager and click the “Device Software” tab.

If you don’t see your BlackBerry model in that list, then you need to get the latest device software. You can download it at this site, maintained by RIM. Find your carrier in the list and then select the software for your particular BlackBerry model on the next page.

This BlackBerry problem is documented in this Knowledge Base article from the BlackBerry Technical Knowledge Center, which you can consult for complete details. If you have Desktop Manager 4.3 and are experiencing problems with Blackberry Curve, Pearl etc, please read this.

Basically, the Desktop Manager alone is insufficient for installing third-party applications onto your BlackBerry; you also need a copy of the "handheld code" or "handheld software" installed on your desktop machine. The handheld code is generally carrier-specific and it's recommended that you visit your carrier's website to obtain the version optimized for your device. Here are a few links for your convenience:

• Cingular Wireless - BlackBerry 5810, 6210, 6710, 7210
• Cingular - BlackBerry 5810, 6210, 6280, 7280
• Nextel - BlackBerry 6510
• T-Mobile USA - BlackBerry 6230
• T-Mobile USA - BlackBerry 7230
• Verizon Wireless