Problem in accessing NText from MS SQL in Yii framework

When I am trying to read all the values in the table which has nText field, i am getting the following exception.

CDbCommand failed to execute the SQL statement: SQLSTATEHY000: General error: 4004 General SQL Server error: Check messages from the SQL Server 4004 (severity 16)

I guess its the problem with php PDO.

Is there anyway to access nText values other than the sql cast method?

Could you please paste the problematic SQL? (turn on CWebLogRoute to see it)