pgp decryption Failed - 2

[nealpd at bellsouth.net]

 We are using gnupg version 1.2.1.  When our customer sends in an 
 encrypted file we are unable to decrypt it because it keeps getting an 
 error of "pgp decryption Failed - 2".   The customer can then start 
 completely over and encrypt the file again, send it through and it 
 works fine then.  The file always fails on the first couple of tries 
 though.  They have asked us to research and find out what the "pgp 
 decryption Failed - 2" error message means and I can find nothing in my 
 documention to tell me what it is.