Ok. It's working. I just need to get one last piece right.
The words are all joined, so I need to put a comma in between, and preferably drop each word one line down. Which means I have to have a string like this: ",\n". But I don't seem to know how to do it right, because i get an error with this line:
str_cat(newString,WordText+",\n"); ...in this code:

Code:
myFile = file_open_read(fileString);
	if(myFile == 0) {fileOpen = 0;}
	var i = 0;
	while (i < 91)
	{
		file_str_read(myFile,WordText);
		str_cat(newString,WordText+",\n");
		str_cpy((testing.pstring)[0], WordText);
		i += 1;
		if (i >= 91) 
		{
			file_close(myFile);
			fileOpen = 0; 
			myFile = file_open_write(fileStringCopy);
			file_str_write(myFile,newString);
			file_close(myFile);
			break;
		}
		wait(1);
	}


I searched the manual, but found nothing to help me.