Looks like you probably have a huge tree of folders? I would increase your memory limit. I always run my sites at at least 128M, and you're at 32M.

Hopefully I can change this setting as I'm running the site at 1&1 shared hosting.
Is this done by a php.ini and "memory_limit"? Where or in which folder should I put this php.ini?

Thx UncleCheese!

/edit: I will try the info from this thread: http://www.silverstripe.org/general-questions/show/269756#post269756

/edit2: Problem seemed to be solved with php.ini and an increased memory_limit from 40M to 128M. My info.php reports 128M but I still get this error when trying to go to "Files & Images":

Fatal error: Out of memory (allocated 32243712) (tried to allocate 44 bytes) in /homepages/10/d181445061/htdocs/silverstripe/sapphire/core/ViewableData.php on line 77

Why doesn't it allocate the avialable memory, is there something to be configured in Sapphire or ViewableData.php?

/edit3: It works for now with ini_set('memory_limit', '128M'); in ViewableData.php

Platypus

You modified ViewableData.php? You should never hack the core SS code. Put your ini_set() in your mysite _config.php.

Yes, it was an act of desperation... I did this to several core files - but I have removed the modifications with backup/original files already. I didn't know that I had to put ini_set() right in the header of mysite/_config.php, I tried this file of course.
There's always something new to learn with Silverstripe and I like it ;-)

Thanks again for you're help and advice UncleCheese!