A few posts ago I explained how you can connect Ubuntu to SQL Server for PHP. All worked well until you tried to execute stored procedures. (It worked fine if you wrote the query, but not so much with mssql_execute() function). It would result in an error like this:

Warning: mssql_execute() [function.mssql-execute]: stored procedure execution failed

Well I did a little searching around and found out it appears to be a freetds issue, where you need to alter the freetds.conf file. This article tells you the correct config (tds version = 8.0 is the secret I believe), however it tells you the wrong location of freetds.conf for Ubuntu. Within Ubuntu you will find this file in /etc/freetds/freetds.conf. You will need to add the following (with your host and port of course):

host = xxx.xxx.xxx.xxx
port = 1433
tds version = 8.0

In my file I already had a [global] section and I just added it into there. After saving these settings into that file I was then able to call my stored procedures with no problem!