Application vault won't install anything

[sunmacet]

When I try to install software from appvault I get these:

Program execution failed, please check Plesk Control Panel's log files for details (Content-type: text/html
Usage: configure (install | upgrade <version> | configure | remove)
). Contact your system administrator for assistance.

Site application installation failed: Content-type: text/html
Usage: configure (install | upgrade <version> | configure | remove)

Where to find this log file for details? How to fix this? Upgrade to Plesk 8.6 didn't help at all.

 

[sunmacet]

I am diggin more into this problem. I have found that usermng can't get the quota of users:

repquota: Mountpoint (or device) / not found.
repquota: Not all specified mountpoints are using quota.
usermng: Unable to get quota parameteters from /usr/sbin/repquota

However / is mounted with usrquota and all seems to be just fine. How to get more info about this problem or how to find more questions/answers?