My friend's forum has error:
MySql Error returned: Got error 28 from storage engine
MySql Error code: 1030
So I try to read on Internet and help him Open Forum again ...
One or more partitions on your server is out of space or doesn't have enough space to complete this operation. You need to shutdown your forums and contact your host immediately. You or your host will need to find out which partition is low on disk space and either add more space or free up some.
Talk to your webhost to resolve this problem. And also try to repair/optimize your database through phpMyAdmin.
I optimized the tables in phpmyadmin, bringing them down from around 100mb to 50mb and it may fixed the problem.
Clear cache should provide some help for those facing the same problem.