By default, a timer is executed only on the network (that is, the server connection) it's been started at. If you type /timer (without any parameter) you'll see a list of all currently running timers:
* timer <N / name of timer> [<repetitions>] <delay> delay <timer command> (<network>)
If you want a timer to be executed on all connections instead, or another connection than the "current" conection (the connection you're starting the timer at), have a look at the /scon and /scid commands.
The "only if that nick is online" thing is more difficult. Your script needs to call a /who <nick> or /ison <nick(s)> first, and parse the respective raw reply of the server. Maybe mIRCS notify list feature will help you: if the nick had been added to the notify list, you can use the $notify(<nick>).ison identifier directly, without the need for a "separate" check via /who or /ison.
Last edited by Horstl; 21/10/08 06:50 PM.