Wadia 301 skipping

My Wadia 301 has started skipping. It only happens on certain disks. It plays a bit and then jumps back about 4 or 5 seconds. Any ideas? Dirty lens or problem with laser pickup perhaps?
Usually this means either the lens is out of alignment or there is dirt on rail. I'd give Steve Huntley at Great Northern Sound a call.
Why is it that everybody seems to have trouble contacting Wadia? I've emailed them a couple of times (just with some questions, I haven't had the need to get my cd player serviced).

Every time Wadia has replied within 24 hours.