Cannot edit gallery pages

[biber]

I've build a site with some galleries (malabu.de/pw). Everything works fine, but there is one page (meine Heimat) I cannot edit like the other ones, although it uses the same template as all the other ones. I also can not find any differences in the settings. I write something in the fields belonging to the pictures (description, caption etc.), click 'save' and my text vanishes. I dont get any response or error message. I am able to write text directly into mysql (via phpMyAdmin).

Could anyone help?

update:

After I added more Pictures I cannot add any text to the Photographs at any page, but adding more Pictures is still possible. Is there any limitation of how many Pictures a page may contain? (actually about 100/page)

[biber]

In the server's log I found the answer: PHP Warning:  Unknown: Input variables exceeded 1000. To increase the limit change max_input_vars in php.ini.

After setting this option to 10000 (don't know this value is choosen reasonable) everything works fine again.