ADOP Prepare Phase Fails with ORA-31011: XML parsing failed

While applying Patch on a test instance (R12.2.5), Prepare phase failed with error ORA-31011: XML parsing failed

Complete error message from adop logfile
==================================

[aptest12@localhost <RUN> ]$ adop phase=prepare

Enter the APPS password:
Enter the SYSTEM password:
Enter the WLSADMIN password:

Validating credentials.

Initializing.
    Run Edition context  : /test12/applmgr/fs2/inst/apps/test12_localhost/appl/admin/TEST12_localhost.xml
    Patch edition context: /test12/applmgr/fs1/inst/apps/test12_localhost/appl/admin/TEST12_localhost.xml
    Patch file system free space: 1130.34 GB

Validating system setup.
    [ERROR]     Failed to execute SQL statement:
select node_name from FND_OAM_CONTEXT_FILES
where NAME not in ('TEMPLATE','METADATA','config.txt') and
CTX_TYPE='A' and (status is null or upper(status) in ('S','F'))
and EXTRACTVALUE(XMLType(TEXT),'//file_edition_type') = 'run'
and EXTRACTVALUE(XMLType(TEXT),'//oa_service_group_status[@oa_var=''s_web_admin_status'']')='enabled'
and EXTRACTVALUE(XMLType(TEXT),'//oa_service_list/oa_service[@type=''admin_server'']/oa_service_status')='enabled'

    [ERROR]     Error Message:
    [ERROR]     ORA-31011: XML parsing failed
    [ERROR]     ORA-19202: Error occurred in XML processing
    [ERROR]     LPX-00229: input source is empty
    [ERROR]     ORA-06512: at "SYS.XMLTYPE", line 272
    [ERROR]     ORA-06512: at line 1 (DBD ERROR: error possibly near <*> indicator at char 208 in '    select node_name from FND_OAM_CONTEXT_FILES
    [ERROR]         where NAME not in ('TEMPLATE','METADATA','config.txt') and
    [ERROR]             CTX_TYPE='A' and (status is null or upper(status) in ('S','F'))
    [ERROR]             and EXTRACTVALUE(<*>XMLType(TEXT),'//file_edition_type') = 'run'
    [ERROR]             and EXTRACTVALUE(XMLType(TEXT),'//oa_service_group_status[@oa_var=''s_web_admin_status'']')='enabled'
    [ERROR]             and EXTRACTVALUE(XMLType(TEXT),'//oa_service_list/oa_service[@type=''admin_server'']/oa_service_status')='enabled'
    [ERROR]     ')
    [UNEXPECTED]Error occurred identifying Admin server node


[STATEMENT] Please run adopscanlog utility, using the command

"adopscanlog -latest=yes"

to get the list of the log files along with snippet of the error message corresponding to each log file.


Cause:

fnd_oam_context_files table has incorrect information  or the table is corrupted


Solution:


1. Login to sqlplus as applsys and take backup of fnd_oam_context_files table.


SQL> conn applsys
Enter password:
Connected.
SQL> create table fnd_oam_context_files_bkp as select * from fnd_oam_context_files;

Table created.

2. Truncate Table fnd_oam_context_files

SQL>  truncate table fnd_oam_context_files;

Table truncated.


3. Bring down MT Services

4. Run Autoconfig to populate fnd_oam_context_files  with right information.