WSS 2.0 : Explicit Impersonation cannot work with SPRoleCollection
The following code will fail if the user doesnot have Admin previlage
SPRoleCollection RC = CurrentWeb.CurrentUser.Roles;
The CurrentWeb.CurrentUser.Roles method requires Manage Site Groups permission and the impersonation does not work with SPRoleCollection
RESOLUTION:
-Write a custom sharepoint webservice and pass the administrator (networkcredentials) credentials to the webservice to retrieve the roles.