issue when updating users info

Hi
I am using the SOAP api to update a users email address via the UpdateLoginWithPromoCode method. This seems to work, however, when I then go and call the 
GetAccountInfo method, using the same session key, I am getting the following error. Which seems odd since I can continue to do more email update calls with the same session id.
any thoughts?
micah

array (
  0 => 'System.Web.Services.Protocols.SoapException',
  1 => 'Server was unable to process request. ---> Tessitura.WebAPI.TessituraException',
  2 => 'TESSITURA_ACCESS_DENIED_EXCEPTION',
  3 => 'The method called requires the user to be logged in. SESSION KEY',
  4 => '5PPHTUGLOQFE6IF310W8H3KVDKSAOOIJE800NHEH465PF3HKEGGVASULOS6EL900
   at Tessitura.WebAPI.TessituraException.Throw()
   at Tessitura.WebAPI.TessituraAccessDeniedException.Throw()
   at Tessitura.WebAPI.Tessitura.GetAccountInfo(String sSessionKey)
   --- End of inner exception stack trace ---',
)