[pdftex] no room for a new dimen ... !?

[Erwin Achermann]

Hi all, 

Miktex allows to install and update packages from CTAN very comfortably,
this is why i update all the packages and install new packages quite
often in recent times. So often that i cannot remember what newly added
or updated package broke my pdflatex version of my book. However i'am
now facing the error: 

(C:\Program Files\MiKTeX\tex\context\base\supp-mis.tex
loading : Context Support Macros / Missing
! No room for a new \dimen .
\ch at ck ...rrmessage {No room for a new #3}
                                          \fi 
l.165 ...extdepth \do \newdimen \nextdepth
                                           \fi
)

This is not one of those infamous 'TeX-capacity exceeded' incarnation,
is it? I don't think either that this is a problem of supp-mis.tex,
right?  However, where and how do i increase the room for new dimens, or
what could be a feasible reason why pdflatex uses more dimens than good
old latex, which digests the file without any problems? 

Thanks for any hint or pointer to make my ignorance yet a bit smaller

Cheers
Erwin