If your TV still powers on but has software bugs, it is safer to use the official update method:

24-inch (60 cm) HD Ready LED (1366 x 768 resolution). Ports: 2 x HDMI, 2 x USB. Finding the "Dump" File

Official manufacturer websites like Panasonic Support usually provide "update" files (via USB), not raw "dump" files. A "dump" file (often in .bin format inside a .rar archive) is usually found on technician-focused forums or spare parts sites.

Are you trying to using a programmer, or just looking to update the software via a USB stick?