I'm too getting this error when running command line.  Actually, I'm using some
callbacks (check-html, check-link).  
Does this error (Panic/4273) indicate that the scan/mirror will be incorrect
or incomplete, or can I just ignore the error?
Regarding going back to version 3.3.  Would I still be able to use my callback
code, as is?  Any important functionality differences?
Thanks.