Hi

i have this from the metalink and it is from Oracle Support:

"You can offline drop the datafile specified in the error message, open the database, take the tablespace offline, drop the tablespace and recreate it.

startup mount your database
alter database datafile 'filespec' offline drop;
alter database open;
alter tablespace TEMPTABLESPACE offline;
drop tablespace TEMPTABLESPACE;
delete datafiles associated with the TEMPTABLESPACE from the OS
create tablespace TEMPTABLESPACE datafile 'filespec' size xxm;
"
this is what oracle is saying, you can follow there advice