What are the limits? How can we set them?

Hi there,

(look into attachment, please)

When uploading files to multiple (no limits) imagefield, I still get problem
near 40-50 files. The form stopped displaying, as you see on the image.

Earlier - when uploading 10 or 20 images - there is no problem at all.

It looks like it happens because of reaching some memory/quantity limit.
But which one?

All I could set, I did set to very high values like hundreds of MB, to be sure.
I mean PHP values in php.ini, values in Drupal admin, etc.

And still I have problems with setting up a gallery with only 56 files. Why?
What are the limits of Filefield/Imagefield/Imagecache system?

[running last core, last devs from Imagefield-like modules, CCK, etc.]

Szy.