#2313 files aren't displayed but there / blank page saving content

[webwitch]

more.groupware version:
moregroupware [Release 0.7.4 - not2early]

PHP version:
5.2.8 / 5.2.8 / 4.4.9 / 5.3.1 (all available)

MySQL:
5.0.67

Hey,
I searched for some hours in the existing bugs but couldn't find my problem.
I'm not a tech person so I don't have access to log-files.

This is my problem:
I installed files module from latest version at source forge.
I can add a blank file. When I edit the file and add content, I receive a white page after "save". The file does then not contain the new text.
Same when I create a file with content.
Same when I try to upload a file, except that when I check my FTP-folder, the uploaded files are there. I can only see them in FTP not in the overview at groupware. The list only shows empty files. No files that have been uploaded, no files that contain text.

I only tried the whole thing with plain text.

Would be great if someone could help.
thanks a lot!