Installation problems - fatal error

Hi,
I'm trying to install xerte on my web server. I uploaded files, changed permissions, setup database, went through set up and it said all ok. However, when I go to the folder for my installation I get:
Fatal error: Class 'Xerte_Validate_FileMimeType' not found in /home/myfolder/public_html/xerte/plugins/file_uploading-mimetype.php on line 30

I've tried searching for this error/issue but can't find anything. Any ideas?

I've never seen that either.

The function/class is defined in ./library/Xerte/Validate/FileMimeType.php

Not sure why it is not found. Are there any errors in the logs?