Thanks for quick response!
This message was find in the var/logs/apache2/error.log:
Traceback (most recent call last):
File "/var/www/html/mrf/src/modules/pefile/peparse.py", line 2, in <module>
import os, sys, pefile, json, base64, struct, binascii, time, unicodedata, re
File "/var/www/html/mrf/src/modules/pefile/pefile.py", line 26, in <module>
from past.builtins import cmp, long
ImportError: No module named past.builtins
In the access.log there is nothing strange.