I've installed the new css.php file. so it helped with bringing back spaces after comma's.
but it also gives a new thing: every page- or post load, show for a part of a second also a partial black screen. first the post/page is loaded, and then the partial black screen followes. same effect when I set Compress to "no".
how come?

If you haven't you should apply all patches.

I did. all four.
so...

Example? URL showing issue

http://www.vvbeetgum.nl/

please test this: switch to the twenty-eleven theme and see if it exhibits the same behavior

I would also test with all the plugins deactivated.

I found the plugin: Lightbox 2.
thx guys