Trying to multiplicate pages with Adobe Acrobat and Java

Hello adobe Community,

I'm trying to implement a simple java script to copy a certain amount of pages from my own document. It should be implemented with a dropdown-menu, but even with a simple button it did not work. I read in "Developing Acrobat Applications Using JavaScript" how to do it and it states:

For example, the following code inserts pages 2 through 5 from mySource.pdf at the beginning of the
current document:
this.insertPages({
nPage: -1,
cPath: "/C/temp/mySource.pdf",
nStart: 2,
nEnd: 5
});

I changed out cPath with the path of my current document and also with "this.path" (without ""), and on button press, only my alert shows up at the start of this script, but not in the end. What am I doing wrong? 

Kind regards

NW