Package kvsetkeys Error: Undefined key `Rect'

[edobm]

Hi,
when using pax the following error message comes up two times during compilation:

! Package kvsetkeys Error: Undefined key 'Rect'.See the kvsetkeys package documentation for explanation.Type H <return> for immediate help.... }

I read about this issue and that manually loading the etexcmds package should solve it. But it doesn't work.

I use the following commands directly before \begin{document}

\usepackage{etexcmds}
\usepackage{pax}

Any hint on this issue?

Many thanks,
Edo