Run the code to create the function. Sample code for calling it is listed in the comments at the top.
If you have a file name and are making an archive:
SELECT 'C:\somefilename' + dbo.DBA_udfDateStringReturn(getdate(), 1, 1) + '.txt'
will return "C:\somefilename20090205-155737300.txt"
If you don't need it down to the millisecond then you can do this instead:
SELECT 'C:\somefilename' + dbo.DBA_udfDateStringReturn(getdate(), 0, 1) + '.txt'
Will Return: will return "C:\somefilename20090205-155737.txt"
PS> If the code won't parse it is because of unicode characters. Paste to notepad, remove the unicode characters and then paste that into SSMS.