umbraco 6.0.5

uCommerce 3.6.1.13149

I'm getting the following error after install, I can see the Commerce icon in the "Sections" area, however when I click on it no tree loads and I see the following.

2013-06-24 14:12:05,249 [6] ERROR Umbraco.Core.UmbracoApplicationBase - [Thread 26] An unhandled exception occurred
System.InvalidOperationException: Sequence contains more than one element
   at NHibernate.Linq.DefaultQueryProvider.ExecuteQuery(NhLinqExpression nhLinqExpression, IQuery query, NhLinqExpression nhQuery)
   at NHibernate.Linq.DefaultQueryProvider.Execute(Expression expression)
   at NHibernate.Linq.DefaultQueryProvider.Execute[TResult](Expression expression)
   at System.Linq.Queryable.SingleOrDefault[TSource](IQueryable`1 source, Expression`1 predicate)
   at UCommerce.Umbraco.Security.UmbracoUserService.GetUser(String userName)
   at UCommerce.Umbraco.Security.UmbracoUserService.GetCurrentUser()
   at UCommerce.Security.RoleService.GetRolesForUser()
   at UCommerce.Security.SecurityService.UserIsInRole(Role role)
   at UCommerce.Umbraco.Menu.LoadCatalog.CreateRootNode(XmlTreeNode& rootNode)
   at umbraco.presentation.webservices.TreeDataService.LoadAppTrees(TreeRequestParams treeParams)
   at umbraco.presentation.webservices.TreeDataService.ProcessRequest(HttpContext context)
   at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

Dim us As New UCommerce.Umbraco.Security.UmbracoUserService()
us.GetAllUsers()