AVG might be broken in the Pirate Edition... I saw the same thing.

Did it ever work previously for you in PE?

Might be easier for you to use your own AV to scan files. Keep your regular AV updated & then use it to scan new files from LW's saved folder after download.

If it's annoying you to see the error, you can uncheck the scan option (tools > options > transfers > uncheck 'scan files I download for viruses' > ok) then you shouldn't see the 'unable to scan' message.

Or you could use File_Girl's version of PE, which has no AVG included.