Just go to your hard drive –> library –> preferences and open the file “com.apple.dockfixup.plist” with text editor, then remove these:
<dict>
<key>after</key>
<string>begin</string>
<key>path</key>
<string>/Applications/Mission Control.app</string>
</dict>
AND
<dict>
<key>after</key>
<string>/Applications/iChat.app</string>
<key>path</key>
<string>/Applications/FaceTime.app</string>
</dict>
This is if you have problems with both Mission Control and Facetime, if not just remove the one you want to remove. Remember to unlock both the file and the folder it in so that you are allowed to both read and write.
