I don't know if you are aware, but there is an application included with AutoCAD that makes dealing with the operating system a breeze when working with AutoLisp. This is DOSLib.Arx, designed and distributed by Robert Mcneel and Associates.

DOSLib, or DOS Library, is a library of LISP-callable functions that provide Windows operating system and DOS command-line functionality to various CAD applications, including AutoCAD and IntelliCAD.
DOSLib extends their LISP programming languages by providing the following
functionality:

• Drive handling functions to change between drives and check disk space.
• Path handling functions to manipulate path specifications.
• Directory handling functions to create, rename, remove, select and change directories.
• File handling functions to copy, delete, move, rename, and select files. Functions for getting directory listings, searching and finding multiple instances of files, and changing attributes are provided.
• Print handling function to get and set default printers, and spool files.
• Initialization file handling functions to manipulate Windows-style initialization (INI) files, and Windows Registry access functions.
• Process handling functions to run internal DOS commands or other programs.
• Miscellaneous functions, like changing the system date and time, and displaying Windows message boxes.

This is a great way to promote yourself or your company.

DOSLib Function : dos_splash

Syntax : (dos_splash filename duration)

Arguments :

• filename - A 256-colour Windows BMP File.
• duration - Duration Time in Seconds.

Example : 

	(dos_splash "afralisp.bmp" 5) 

This will display a Windows Browse for Folder Dialogue box and will return
a fully qualified path to the selected directory.

DOSLib Function : dos_getdir

Syntax : (dos_getdir title [path])

Arguments :

• title - A dialogue box title.

• path - An existing directory.

Example : 

	(setq udir (dos_getdir "Select a Directory" "c:\\")) 

Displays a Windows common file open dialogue box that will allow you to select
multiple files.

DOSLib Function : dos_getfilem

Syntax : (dos_getfilem title path filter)

Arguments :

• title - A dialogue box title.
• path - An existing directory.
• filter - A filename filter string. The filter string consists of two components: a description (for example, "Text File"), and a filter pattern (for example, "*.txt"). Multiple filter patterns can be specified for a single item by separating the filter-pattern strings with a semi-colon (for example, "*.TXT;*.DOC;*.BAK"). The components must be separated by a pipe character ("|"). The filename filter string can consist of one or more filter strings, each separated by a pipe character.

Example : 

	(setq ufiles (dos_getfilem "Select Drawings" "c:\\drawings\\"
	"Drawing Files (*.DWG)|*.DWG"))

This displays a Windows Message Box. Much more flexible than the standard
AutLisp "Alert" function. Very similar to the VBA Message Box function.

DOSLib Function : dos_msgbox

Syntax : (dos_getfilem text title button icon)

Arguments :

• text - The message to be displayed.
• title - The message box title.
• button - The push button format.
  The allowable values are : 
  • 0 - Abort, Retry and Ignore.
  • 1 - OK.
  • 2 - OK and Cancel.
  • 3 - Retry and Cancel.
  • 4 - Yes and No.
  • 5 - Yes, No and Cancel.
• icon - The icon.
  The allowable values are : 
  • 0 - Asterisk.
  • 1 - Exclamation.
  • 2 - Hand.
  • 3 - Information.
  • 4 - Question.
  • 5 - Stop.

• 0 - Abort
• 1 - Cancel
• 2 - Ignore
• 3 - No
• 4 - OK
• 5 - Retry
• 6 - Yes

Example 

	(dos_msgbox "Continue Batch Process?" "Batch Purge" 5 4)