DataSet's relationships causing problems

[Benny]

I have a large dataset with relationships between DataTables.
I am having an aweful time getting relationships to work.

1. I can't access related rows of a datatable's row using
(datarow).Get(related table)sRows() (gives me an invalid cast error)

 
DS.CustomersRow custR = custTA.GetDataByCustomerID(customerID)[0];
DS.AddressesRow addR = custR.AddressesRow;
- DS.CommentsRow[] commRs = custR.GetCommentsRows();
 
 

I get the following "InvalidCastException" at the "->":

Unable to cast object of type 'CustomersRow[]' to type 'CommentsRow[]'.

Even though the signature says it returns 'CommentsRow[]'

2. I cant access a one-to-one related row using (datarow).(related
table)Row

 
AgentsTableAdapter agentsTA = new AgentsTableAdapter();
DS.AgentsRow agentsR = agentsTA.GetDataByLogin(id, pwd)[0];
...
string _role = agentsR.RolesRow.RoleName;
 
 

RolesRow is suppose to be a child row of the current row.

This is rather urgent so I really appreciate any help.