If you have message like ‘General error: 20018 Unicode data in a Unicode-only collation or ntext data cannot be sent to clients using DB-Library (such as ISQL) or ODBC version 3.7 or earlier.’ probably one of your columns is invalid.
In my scenario i had one column nvarchar(max).
Solution to that problem is to build query using CAST f.e.:
‘synopsis’ => new Zend_Db_Expr(‘CAST(synopsis AS nvarchar(4000))’),