exp giving me an error

Hi:
I am running an export and have the OS level parameter set  NLS_LANG=.AL32UTF8.

When I run my export I get the error Export done in AL32UTF8 character set and AL16UTF16 NCHAR character set

So I comment out the NLS_LANG parm and get the error:

Export done in US7ASCII character set and AL16UTF16 NCHAR character set
server uses AL32UTF8 character set (possible charset conversion)

I checked the database and these are my nls settings:

PARAMETER                      VALUE
------------------------------ ------------------------------
NLS_LANGUAGE                   AMERICAN
NLS_TERRITORY                  AMERICA
NLS_CURRENCY                   $
NLS_ISO_CURRENCY               AMERICA
NLS_NUMERIC_CHARACTERS         .,