echo("Flushed Texture Cache");
You need quotes there or it will give a syntax error.
commandtoserver('messageall',"<color:ffffff>Flushed Texture Cache.");
Nope. Looks like your trying to mix clientside and serverside code there.
if you're trying to tell everyone in the server (which for this I wouldn't recommend because no one gives a stuff and you'll end up annoying them if you keep doing it) the code is
for serverside:
messageAll('','message');
for clientside:
commandtoserver('messagesent','message');
What you would want in this case is something to message only yourself, something like
clientCmdChatMessage(dont know arguments here and too tired to dig them up);
or even
clientCmdCenterPrint("message",3);