Knoppix hangs with some USB stick memories

It has been checked with 2 versions of Knoppix (3.4 and one of erlier) and 2 different PCs.
We checked 3 different memory sticks. All of them worked fine on Win2000 (machine different than those running Koppix, but I assume it makes no difference).
One memory stick (USB 1.1) worked without problems. A new dir is created in /mnt, we didn't try any transfers.
One (USB 2.0) is identified, but Knoppix hangs after about 60secs after the stick is inserted. No new dir created in /mnt. lsusb lists the device.
One (unknown USB version, but most probably 1.1 as it is quite old) hangs after about 2 minutes. No new dir created in /mnt, system slowed down noticeably.

Knoppix never makes any output before hanging, it just freezes. Hardware reset is neccessary.

Has anyone experienced such behaviour?
Is there any way out of it?