>>Here is my code:
>>FUNCTION GenerateLawLabelBarcode
>>LPARAMETERS ...
>> .......
>> GenerateLawLabelBarcode(....)
>> return ....
>>ENDFUNC
>>
>>I have an error saying that a file "GenerateLawLabelBarcode" does not exist.
>>
>>Please, help.
>
>You can't do that! A function or procedure can't call itself.

In addition to the other relies you got ("yes, you can!"), recursion (i.e., a function calling itself) can in fact be very useful. For example, the following pseudocode will process all files in a directory, including subdirectories:

Function ProcessFiles()
For every file in directory (including directories)
  If it is a file
    Do something
  If it is a directory
    Invoke ProcessFiles() for the subdirectory
Next

Now, try to do the same without recursion. It should be possible, but much more complicated.