stored procedure execution failed in PHP

Hi all !

I have Apache2 + PHP5 + FreeTDS + mssql.so running in Ubuntu Server 8.04

We have a website, using PHP scripts wich connects to a SQL Server to 
fetch information.

The site was created by another person, not me. And he doesn't use 
Unix/Linux, only Microsoft, so all test he has done is
using IIS and MS SQL Server. And says everything works fine.

But in this server, Linux + Apache, We have some problems.

In the main page, he runs  a stored procedure and when loading the page 
we get:

    "stored procedure execution failed in XXXXX"

you can see the page at: https://tesoreria.villadealvarez.gob.mx

and in freetds.log, the only message that looks strange to me is this:

12:23:02.010478 setting column 2 NULL bit
12:23:02.010491 tds_submit_query(): state is PENDING
12:23:02.010506 tds_client_msg: #20019: "Attempt to initiate a new SQL 
Server operation with results pending.".  Connection state is now 1.
12:23:02.010601 Sending packet


I have PHP 5 , Apache 2 and FreeTDS version 0.63


Any ideas ?  I'm new to FreeTDS and is the first time I set up a Linux 
server to work with SQL Server.

Thanks for ypur help.