ORA-01110: data file 6: '/areadb/datafile/credittestdata01.dbf'

Error Raise
SQL> shutdown immediate
ORA-01116: error in opening database file 6
ORA-01110: data file 6: '/areadb/datafile/credittestdata01.dbf'
ORA-27041: unable to open file
HPUX-ia64 Error: 2: No such file or directory
Additional information: 3
SQL>
SQL>

Solution
SQL> alter database datafile 6 offline drop;

Database altered.

SQL>
SQL>shutdown immediate