How can I fix this?
By ensuring that time has at least 1 column before calling your function. At the moment, it is empty since it doesn't even have one column.
Unfortunately, time and the poorly named t, are global and you've just fallen foul of one of the many problems with global variables. It's hard to keep track of their state since any piece of code can modify (or not modify when it should) the state of a global variable.
My recommendation would be to rewrite your code so it doesn't use global variables at all. Unfortunately, we don't have enough information about it give more advice.