Letter class report error at activateDepartmentInfo
The letter class dtuletter.cls
generates an error
(./doc_dtuletter.out) (./doc_dtuletter.out)
! Undefined control sequence.
\@begindocumenthook ...fi \activateDepartmentInfo
{\lang }{\department }\fro...
l.51 \begin{document}
The part of the code with activateDepartmentInfo is commented out.