Application error while connecting from SPS server to his DB server.

[Shaulian]

Hi,

I have two share-point servers. One is the application server which holds the IIS part (Lets call it SP-IIS), and the second is the database for share-point (Lets call it SP-DB) and is Sql-Server 2000.

My team has developed a web-service which somtimes need to read data from a sql-server which seats on SP-DB.
While developing this web-service on our developing server, we used the real SP-DB server and it worked great !
But when we transfered the web-service to SP-IIS the web-service couldnt connect to the database sitting on SP-DB.
The exception is : "Request for the permission of type System.Web.AspNetHostingPermission failed" and being thrown on SqlConnection.Open().

More details :
A) On the SP-IIS server I created another application pool which run under an adminstrator user on both SP-DB & SP-IIS.
B) I added this user to the IIS_WPG group.
C) Also gave this user permissions on the Sql-server as db_owner, and reading permissions on the database it needs to read.
D) There are no firewalls between the SP-IIS and the SP-DB.
E) In the application, i tried to put in the connectionString two different users which are fully allowed to the SP-DB database. The first of them is the user which we developed with and worked great, and the second is the user which mentioned on A+B+C above. both of them arent working in the SP-IIS.

Please help.

Thanks,
Shauli