Postscript: someone from audioblog.com has been in touch and just my luck - they've never seen this problem before. They're working on a solution. I'll report back when and if they provide one.
Some weeks later: bummer. The audioblog.com people can't duplicate or solve my problem so we've agreed to cancel my subscription and refund my money. Sad. It looked like a great and affordable tool. At least their help staff were very pleasant to deal with - responsive and understanding. The problem has to be a software conflict I reckon. Never mind. Time to move on!