07-26-2006 12:59
<ObjectChatColor value="0, 0, 0, 0" />
<ScriptErrorColor value="0, 0, 0, 0"/>
<AgentChatColor value="0, 0, 0, 0"/>

alpha 0 means its not visible

Settings.xml in

C:\Documents and Settings\**yourusername\Application Data\SecondLife\user_settings

is wrong, delete the file
or
manually find and change them to something like this; (red,green,blue,alpha)
<ObjectChatColor value="1, 0, 0, 1" />
<ScriptErrorColor value="0, 1, 0, 1"/>
<AgentChatColor value="0, 0, 1, 1"/>

Just so SL can get alpha and then you just set whatever color you want ingame should work.