If you have LV 7.0, you can select save VI with options for opening the VI in 6.1 version. Remember that you cannot go back to 6.1 if you have LV 7.1. I have attached 6.1 version of your VI here.
The Search and Replace String function has an input called "replace all?". The default is false. Wire a true to it. Right clicking on the function and selecting Help would have gotten you this information.