is wrong... You must give the timer a higher interval
But you are using the timer wrong. You should FIRST disable the timer, then set a interval, then - if you want to run the timer - you enable the timer again.
I'm not able to check the zip file at the moment but a best guess from the error message is that you are attempting to set the interval of a timer to a value of zero or less. If you are setting a timer interval I suggest putting a log statement immediately before that line of code to show you what value is actually being set.
Nb. Manfred must have been replying at the same time as me.