Got it sorted. If anyone is interested, I have a little program installed which retrieves IP addresses (the real server addresses, not pprune or anything else) and uses them to access the net. This makes surfing the favorites faster.
Collecting the real IP addresses is one of the highlights (and in this case the downside) of MODEM WIZARD.
A new retrieval (which should be done every 30 days....) solved all the problems.