[Orgmode] :export: tag shows up in headings of output pdf

[phaebz]

I am using org-mode 7.3 release.

Problem: A file such as

* heading to be exported :export:

* some other heading

gets exported to

1. heading to be exported :export:

With a literal :export: tag in the pdf output heading. I have not customized 
any relevant export options.

Do I miss something?

Any tips / hints are much appreciated

Michael Bach