[EP-tech] call of obsolete function makes trouble

[Thomas Lauke]

During reindexing the archive (for use of xapian) I get the following error message: 

./bin/epadmin reindex repoID eprint

You are about to reindex "eprint" in the A401sandbox repository.
This can take some time.

Number of records in set: 1161
Continue [y/n] ? es
Can't call method "get_datestamp" on an undefined value at /opt/eprints3/Eprints/bin/../perl_lib/EPrints/MetaField/Subobject.pm line 264.

What's wrong? How to fix this problem for 3.3.1[12]?

Tia
Thomas