psaerror / file_get_contents() failed

[mc5000]

I am getting errors if I try to open the "IP-address" or "systemtime" (don`t know the button-text in english) in the plesk admin panel:

file_get_contents() failed: Empty error message from utility.
--------------------------------------------------------------------------------
0: /usr/local/psa/admin/plib/common_func.php3:2391 psaerror(string "file_get_contents() failed: Empty error message from utility.")
1: /usr/local/psa/admin/plib/class.IPAddressesList.php:130 is_virtuozzo()
2: /usr/local/psa/admin/plib/class.cList.php3:94 ipAddrList->fetchIPAddrList()
3: /usr/local/psa/admin/plib/class.cList.php3:114 ipAddrList->fetchList()
4: /usr/local/psa/admin/htdocs/server/ip_aliasing.php3:130 ipAddrList->init()

and

file_get_contents() failed:
--------------------------------------------------------------------------------
0: /usr/local/psa/admin/plib/common_func.php3:2391 psaerror(string "file_get_contents() failed: ")
1: /usr/local/psa/admin/htdocs/server/sys_time.php3:16 is_virtuozzo()

Yesterday I've done the last base-package update.

Any ideas?

Thanks
MC