I know this is old, but...BUMP!
The 'Database Link Broken' is caused by the SQL server database opening and closing all the time so the software thinks the database is closed when in fact it is not. By default, when the SQL database is created, it is created with the SQL db option 'Auto Close' as 'enabled'. Changing this to 'disabled' will allow the DB to be open all the time and thus run continuously and you will not see this error anymore.

Hope this helps!