Question about Roles in AmoAdventureWorks sample code

Question

I'm working with this sample in both Visual Studio 2005 and 2008 and the 2005/2008 AmoAdventureWorks sample and Sql Server 2008 Standard edition. I've made two changes to the AmoAdventureworks project, both in Program.cs. First I put an immediate return in the CreateCurrencyRatesMeasureGroup method to avoid the issue of semiadditive measures not being available in the Standard Edition. Second in the CreateRolesAndPermissions method for the reader role I used this statement:

role.Members.Add(new RoleMember("EIT\test1")); // e.g. redmond\johndoe

instead of:

role.Members.Add(new RoleMember("")); // e.g. redmond\johndoe

and then

role.Update();

gets this exception:

{"The following system error occurred:  No mapping between account names and security IDs was done. .\n"}

If I use this statement:

role.Members.Add(new RoleMember("EIT\test1", "S-1-5-21-107385321-1855232891-3196306309-513")); // e.g. redmond\johndoe

it runs to completion and creates the cube. That is a valid user\sid combination in our domain and as a Server Admin in Analysis Services I can browse the cube.

However if I go into SSMS 2008 and open the AmoAdventureWorks AS database, then open roles and right click on Readers -> Properties -> Membership it shows S-1-5-21-107385321-1855232891-3196306309-513 as the user for this role.

If I add a user and immediately remove that user and click ok I once again get a dialog box with:

The following system error occurred:  No mapping between account names and security IDs was done.

Will someone please explain what I'm doing wrong or missing here?

Thanks

John