Dennis Fokker

Right, thank you, that was all I needed to hear, sorry for the trouble.

My bug isn't about the scoreboard command though, as I said, the problem is that the achievement command can't find the teamkill.color statistic.
I'm not requesting different ways to get the same result, I'm reporting a bug that should get fixed.

@ Kumasasa: Actually you can do +1 a statistic (not score), though nothing more, try it out yourself I'd say.

What error did you recieve?

Yet still, have you tried out the command I handed to you?
Since it works fine for me it'd be rather strange if it wouldn't for you.

The forum itself says you can also use statistics:

stat_name
Must be either:
• achievement.achievement_name, where achievement_name is a valid achievement identifier
• stat.statistic_name, where statistic_name is a valid statistic identifier
• * to represent all achievements

In case you still are not convinced, try it out yourself with a command like:
/achievement give stat.useItem.diamond_hoe
Note that take won't take 1 from the statistic 'counter', but instead will do nothing (give obviously will do +1)

@Sonic
I was refering to statistics, not achievements, you can find all statistics here:
http://minecraft.gamepedia.com/Scoreboard

@Kumasasa
That command too gives the error:
Unknown achievement or statistic 'stat.teamkill.black'
Meaning this bug report is valid.

Confirmed for 1.8.