The Linux 5.3 client README says:
"- The TSM client does not support the default locale for Linux, en_US.UTF-8.
  There may be some files that cannot be backed up with the default locale,
  causing error messages in the dsmerror log and the backup operation
  to stop. To avoid this problem, set the locale LC_ALL to en_US or another
  supported locale, for example 'export LC_ALL=en_US'."

Can this export be issued as a preschedulecmd or is there someplace else it 
should be issued?

David