CompuServe Messages

I am having a problem using AutoCAD scripts. I have an AutoCAD lisp routine that shells to DOS and runs a program. This program takes an AutoCAD drawing and creates a data file and an AutoCAD script file. After I create these files I exit the program and return to AutoCAD. I then use the script file to manipulate the drawing. When the script finishes I don't know how to get AutoCAD to close the script file. I am not able to run the list routine again until I open another script file. If I open another script file it appears to release the original script file and I am able to run the lisp routine. Does anyone have any idea on how to close a script file once it is open?