After some hackering and reading that other people had problems with a lacking space inside a {~a} I managed to get it working.

Here is the code with only marginally small rewrite(added two spaces):
(defun choose-directory (&key (initialdir (namestring *default-pathname-defaults*))
parent title mustexist)
(format-wish "senddatastring [tk_chooseDirectory ~@[ -initialdir {~a }~]~@[ -parent ~a~]~@[ -title {~a }~]~@[ -mustexist ~a~]]" initialdir (and parent (widget-path parent)) title (and mustexist 1))
(read-data))

notice the spaces inside {~a }.

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Kjeld K. B. Massali
denatus@gmail.com
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