Problem with nvarchar output

Hi
I'm using Freetds with PHP5 to access a SQL server but I'm having trouble with the output parameters.
I have two parameters, one SQLINT4 and one SQLVARCHAR. The int is working but I don't get any returns from the varchar.

Is there anything special that needs to be done when outputting nvarchar?

PHP binds,
mssql_bind($stmt, '@ErrorMsg',$ErrorMsg,SQLVARCHAR,true,false,4000);
mssql_bind($stmt, '@OrderNr',$OrderNr,SQLINT4,true,true,8);

SQL parameters,
@ErrorMsg nvarchar(4000) output
@OrderNr Jeeves_OrderNo output


Sql server,
SQL Server 2008 R2

Freetds server,
Ubuntu 12.04 3.5.0-51-generic

Tsql -C
Version: freetds v0.91
freetds.conf directory: /etc/freetds
MS db-lib source compatibility: no
Sybase binary compatibility: yes
Thread safety: yes
iconv library: yes
TDS version: 4.2
iODBC: no
unixodbc: yes
SSPI "trusted" logins: no
Kerberos: no

Freetds conf,
[global]
text size = 64512
[Sqlserver]
host = xxx.xxx.xxx.xxx
port = xxxx
tds version = 8.0

PHP5
PHP 5.3.10-1ubuntu3.12


BR
Ola