IUS trasition coverage problem

Hi

 Am using IUS 6.20-s007 (I have to use this) and I have the following code to perform transition coverage

cmd_trans : coverpoint m_curr_req_transact.m_cmd {bins illegal[] = (IDLE => IDLE);}
 
I followed an example from a Doulos tutorial
 
http://www.doulos.com/knowhow/sysverilog/tutorial/constraints/
 
The first compile error was as follows:
cmd_trans : coverpoint m_curr_req_transact.m_cmd {bins illegal[] = (IDLE => IDLE);}
                                                                                                   |
                                  Range specification for bin must start with ( ' { ' )
 
So I changed the code to:
cmd_trans : coverpoint m_curr_req_transact.m_cmd {bins illegal[] = {IDLE => IDLE};}
 
again the compile failed with:
cmd_trans : coverpoint m_curr_req_transact.m_cmd {bins illegal[] = {IDLE => IDLE};}
                                                                                                             |
                                            Range specification for bin must end with ( ' } ' )

I believe this to be a problem with IUS.  Any advice?