I currently using (temporarily) a Blackberry 8310 Curve with an operating system of 4.2. This has NO version of Blackberry Messenger on it. I need a link to an old version of Blackberry messenger that will work on this phone.
You'll need to download the OS for your device, and it should carry BBM along with it. There should be a link to the OS thru your carrier's website. Once the OS is downloaded, install it on your PC much like you would with a normal program. Plug your device into your computer, then open Desktop Manager, go to Application Loader, and from there you should be able to load BBM.