Problem Reaching Sqlserver2000 Database With Asp.net 2.0 Application When Deploying

I have developped an ASP.NET 2.0 webb application localy on my workstation and have the MSSQL2000 database on a 
server.There has been no problem accessing the database during development. 

Im now finnished and put the application on a web server.

No when i try to access the application i get the following problem as it tries to reach the database:

An error has occurred while establishing a connection to the server. 
When connecting to SQL Server 2005, this failure may be caused by the
fact that under the default settings SQL Server does not allow remote connections.
(provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)

I still use the same database so remote connections are allowed and there are lot of application against that sqlserver already running.

I have anonumouse access and use a domain service account for the application and that very same account is added
as a login to the sqlserver and a domainuser in the database.

I have Forms authentication in my web.config file.


the connectionstring i use look like this:

<appSettings>
 <add key="app1" value="Data Source=server01;Initial Catalog=database1; Integrated Security=SSPI;"/>
</appSettings>


Can somebody please tell me what is wrong and how to fix it. I dont change any configuration betweeen my workstation and the server in web.config

/ in pain!!