Follow this thread to install Java within Classic - Opera Mini on Pixi Plus - working!,

Then go here to download Mobilerar.jar - Mob9.mobi :: File Download System Tools > MobileRar(Mob9.mobi).jar :: Applications > Symbian Zone > Symbian S60 v3 (OS v9.1 - v9.2 - v9.3).

Copy the .jar to your Pixi with Internalz to media/internal/ClassicApps.

Open Classic, and go to your file explorer, (step #4 on Opera Mini thread), and click on Mobilerar.jar. A message will flash about a file transfer.

Copy the .rar you want to extract to media/internal/ClassicApps.

Open Classic, open Mobilerar, go to .rar file, and click 'extract'. The extracted files are now in the same directory.