2 OE 6 problems with blocked addresses

A client is running w98SE with OE 6 on several machines. On one, following either or both prescribed processes for blocking addresses results in the addresses not being saved when exiting OE 6. On another, attempting to get to the list of blocked addresses (in order to unblock one) results in the hour glass display and the machine locks up, forcing a reboot. Any solutions or suggestions for either or both situation(s)? Thanks.