hi, I log in as sysdba and run the script catexp.sql. But when I give command to export i get the following error. (Note:The database is up)

About to export the entire database ...
. exporting tablespace definitions
. exporting profiles
. exporting user definitions
. exporting roles
. exporting resource costs
. exporting rollback segment definitions
. exporting database links
. exporting sequence numbers
. exporting directory aliases
. exporting context namespaces
. exporting foreign function library names
. exporting PUBLIC type synonyms
. exporting private type synonyms
. exporting object type definitions
. exporting system procedural objects and actions
. exporting pre-schema procedural objects and actions
EXP-00008: ORACLE error 3113 encountered
ORA-03113: end-of-file on communication channel
EXP-00008: ORACLE error 1041 encountered
ORA-01041: internal error. hostdef extension doesn't exist
EXP-00000: Export terminated unsuccessfully