Since mIRC scripting is single threaded, I would think that the execution of a 0 second timer set at 0 (infinite) repetitions would lock up your script, and mIRC, since no other process could be started in the delay the timer runs at.
Thus said, if the sockread in your script was coded after the timer, then the socket would not be read.
On the other hand, if it was coded before the timer, it would be read once, but not afterwards.
I do not recommend using a (0-0) timer, and in fact, I can't think of any reason for having a timer running that quickly.
If you need a fast timer, then try a millisecond timer and set it for 5 milliseconds. In my opinion, you probably wouldn't notice any difference.