Before executing a script for the first time it is recommended to select "Check current script" in the "Script" window. This debugging tool does not only checks script syntax. It also checks that all files loaded by the script are accessible. If another script is called by the current script, it is loaded and in turn checked. The debugger also makes sure that the same script will not be called twice during the current script's execution (thus avoiding recursive calls). If a file is not found, the script debugger prompts the user to locate it. Then it may rename the file or keep trace of its location by inserting instructions like "Set directory..." or "Set Vref...". Understandably, it is necessary to call "Check current script" every time once of the files used by the script has been renamed or relocated.