OEX6 not retaining BlockedSenders

I’m tending to a system that won’t retain the OE Blocked Senders list.

It’s a Dell w/WXPHomeSP2, IE/OE6. When the user goes online & checks for new mail, all new mail comes in fine, including twice as many SPAMs as real mails. Blocking senders and domains via the usual route seems to work fine until you close & reopen the program – when you find an empty list!

Any thoughts?