adncep3(): Invalid destination character set: UTF8

Issue with the Patch Admerge :
----------------------------------------
Character-set converting files...
adncep3(): Invalid destination character set:  UTF8

Adncnv error:
  Character-set conversion failed

Please check the adncnv logfile at admrgpch.log.

************* Start of AD Character-set Conversion session *************
AD Character-set Conversion version: 12.0.0
AD Character-set Conversion started at: Fri Jan 27 2012 05:32:18

AD Merge Patch error:
  Character-set conversion failed.

Solution:
--------
To implement the solution, please execute the following steps:

1. Manually set (and export) environment variable NLS_LANG to be American_America.US7ASCII.

2. Run again
     admrgpch -s patches -d mrgd_patches -merge_name mrg_patch

3. Migrate the solution as appropriate to other environments.