Steps to configure Environment variables:
1. Right click on My Computer->Properties->Click on Advanced Tab->Click on Environment variables(at the bottom)
2. Environment Variables window will be opened-> In the you will find “USER VARIABLES” as shown below: Click on New as marked
3. In the pop-up window set variable name to TCLLIBPATH and value to "C:/Program Files/Spirent Communications/Spirent TestCenter 4.40/Spirent TestCenter Application"
4. Click OK.
5. Then open command prompt and use the following command to run the script.