Playing content (such as music and video) is dependent on both the integrity of the disc, and also the capabilities of the player. A problem playing back content does not mean that the drive, or the discs are damaged.
LaCie DVD burners are capable of creating DVDs that can play in set-top DVD players. For content to play in a DVD player, however, the files must be organized in a very specific way. To arrange data for use in a set-top DVD player, it is best to use a DVD creating tool.
Many LaCie DVD burners come with a program called Toast. This software can create DVDs that play on set-top players, easily. Anything created using the "Video" mode of the program will play in a set-top DVD player. iDVD (included with Apple's iLife) can also use the LaCie to create DVDs, so long as it is a recent version.
Easy Media Creator is included for Windows computers. This has similar capabilities, and also has a function labeled "Video". Use this to make set-top DVDs.
LaCie DVD burners can also make audio CDs suitable to play in any CD player (like car stereos, portable cd players, etc.) This must also be done using a special tool, rather than simply dragging and dropping data.
Like the "Video" section, there is an "Audio" section to make audio CDs. Drag and drop audio files (MP3s, AC3, etc.) and the formatting will be done automatically.
NOTE: Not all set top DVD players or CD players are capable of playing discs created with a DVD burner. If the disc is created properly, contact the manufacturer of the device with the playback problem, as they may have suggestions that can solve the problem.