Hello oh good men of DBASupport!!!

I am trying to make a dump file out of my database and have been encountering the error

. exporting tablespace definitions
EXP-00008: ORACLE error 1157 encountered
ORA-01157: cannot identify/lock data file 201 - see DBWR trace file
ORA-01110: data file 201: '/opt/oracle/oradata/orcl1/temp01.dbf'
EXP-00000: Export terminated unsuccessfully

The same error occurs when I try to load data using the "imp" command. Please help me out here. This is getting critical for my project.

Thanks in advance.