Well, I looked at your VI and it looks like you have everything setup right. The only thing I can think of is that you are not grounding the control lines when you want to set them low.
As far as your second question is concerned some parallel ports can be bidirectional. The article that you provided explains how you can test if you parallel port is bidirectional, and gives an example on how you would read and write from the data bits.
Also, you may want to try the two parallel port shipping examples in LabVIEW. There is one that uses the data bits, and one that uses the status and control registers. You can find these examples by going to Help>>Find Examples, then search for Parallel.
Shawn B.
National Instruments