SQL needs CAST to return values in query

Question

Gentlemen I manage an application PHP which uses SQL Server 2008 database. After a server migration from the database queries only work by converting with CAST and selecting one by one on SELECT.

When nay use the CAST get this error.

Warning: mssql_query(): message: 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. (Severity 16) in C: Program Files (x86) Netmake V81 wwwroot.php test-connected online site 152 Warning: mssql_query(): Query failed in C: Program Files (x86) Netmake V81 wwwroot Site test-connected.php on line 152 Warning: mssql_fetch_array() expects Parameter 1 to be Resource, Boolean Given in C: Program Files (x86) Netmake V81 wwwroot Site test-connected.php on line 154*

Does the Database server have this outdated ODBC driver?

What I can do to not have to change all the application queries?

Below examples of codes:

    ## Não funciona (Consultas Autuais)
    $sql="SELECT * FROM MinhaTabela";
    $resultado = mssql_query($sql);
    while ($row = mssql_fetch_array($resultado)) {
        echo$row['CampoVarchar']."<br>";
    }

    ## Funciona 
    $sql="SELECT  CampoVarchar , CAST(CampoVarchar AS TEXT)  AS CampoVarchar FROM MinhaTabela";
    $resultado = mssql_query($sql);
    while ($row = mssql_fetch_array($resultado)) {
        echo$row['CampoVarchar']."<br>";
    }