I was too frustrated when I posted my thread. I shouldn't have done that.
I'm relaxed now and thank you for your answers and ideas.
@joea:
I've seen longer lists and the owners claim it works fine. I think that is not the problem.
@Sailor Steve:
my system specs:
Windows 7
Intel i5 750 2.67 Ghz CPU
4 Gb RAM
Geforce GT275
@ jwilliams:
I'll change the order in what you suggested. Makes sense.
@ sober:
the fix you suggest concerns a fix with eneny subs. In my situation that's not the case. (I think...)
@ all:
I uninstall the mods (or at least the most of them) and install them one by one with a test after each installed mod.
Nevertheless, thank you all.