System error when editing user permissions

Hello,

SpiraTest was recently upgraded from v6.0 to v6.1.  I'm trying to edit a user's permissions, but I get a system error as follows:

A system error has occurred... Please click on the 'My Page' link to return to the application

Please contact your system administrator and provide the following details:

Offending URL: __PageSource: mscorlibMessage: Index was out of range. Must be non-negative and less than the size of the collection.Parameter name: indexStack trace:    at System.Collections.ArrayList.get_Item(Int32 index)   at APPLICATION.Web.Administration.Project.ProjectMembership.btnProjectMembershipUpdate_Click(Object sender, EventArgs e)   at APPLICATION.Web.ServerControls.DropMenu.OnClick(DropMenuEventArgs e)   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

Any tips on how to resolve this error in order to edit user permissions?

Thanks,

Anh