I think that if you use an activeX container, property and invoke nodes will work for the document/file or whatever you have in it, so I recommed you to use references to the file you want to use, open an activeX reference in the block diagram, and pass this reference to open, write, save and exit. This can be done easyly using the invoke and property nodes you already know... If not, check for errors between them, sometimes one error makes the rest of the code not to work... Hope this helps.
If you want me to check the program, you can send an example here, but be sure it's LV 5.0, I've nor 5.1 nor 6.0, it can be a way of knowing the problem.
