Make sure you have a recent copy of VISA first. Next, try running the Getting Started.vi that is included with the instrument driver, because it uses the initialize.vi. If this doesn't work there are a few possibilities. It could be the VISA driver, the VI, or the instrument. Try testing the instrument in MAX to verify that you can communicate with it. You might want to upgrade your VISA version or reinstall the instrument driver.
I hope this helps,
Joshua