Since using a debugger tends to elongate the time between the execution of lines in code (because the user needs to manually move the program ahead), data has more time to be processed and buffered, therefore not crashing.

At any rate, I assume you mean http://zim-wiki.org which is a fine thing to be called a script, and has its own, very detailed installation page(s). Along with an FAQ, manual, Bug-Tracker etc.

On the other hand, you might be referring to something else, which in that case, I hope another monk will be more handy with a guess of what you want