Redmine

Hi all,

We faced new problem that did not happen in the past. After restarting redmine server, we may start new issues without any problem, but no one from us (including me, administrator) could change the status or something of each existing issue. We got the following message:
"Internal error
An error occurred on the page you were trying to access.
If you continue to experience problems please contact your Redmine administrator for assistance.
If you are the Redmine administrator, check your log files for details about the error."

I'm "redmine administrator", but I don't know about any log files.
Could someone help me?
1. Where should I find the log files?
2. Any suggestions?
3. Are there any "redmine masters" being in Israel for support?

Thanks,
Vitaly