Note that 5.8.1 was the perl that was binary incompatible.. It was incompatible to 5.8.0. That was repaired in 5.8.2. Thus I would guess that many people dont bother to test much with 5.8.1, and go straight to 5.8.2 and above. You might look to see if Fedora/OSX etc have an upgrade to 5.8.2.