Search server (sharepoint) permissions

I have created an ASP.NET web application that is calling the search.asmx service on a Search Server 2008 Express instance.

When i connect using a domain account that is a local admin on the search box everything works great, however this isn't a long term solution... What permissions to i need to give to the domain account for my web service call to work?

The error i receive when connecting with non-domain admin account is;

Attempted to perform an unauthorized operation

Thanks in advance.

From serverfault GordonB

• http://technet.microsoft.com/en-us/library/cc297197.aspx#section5

  From Fuztak-ulaR