I've had loads of them as well.
Do not worry, it is only a useless messages- the deaths do not show up on your stats etc.
You might also have noted you sometimes get "[Artillery] Playername" as well.
I use custom localization files, so when someone gets teamkilled, it shows the weapon they got killed by.
e.g. Titch [Teamkills- M16A2] CC-Marley
I have noticed that for the majoirty of the time (if not all of the time) you get "[Teamkills] Playername, it is actually an Artilley piece that Teamkills you. Bit of a coincidance... all the messages related to Artillery pieces.
I have also noticed that the messages also most oftenly appear when you die, you get revived, or you respawn.