Hi,
I have Vista as my OS and I found the files in a different place and they appear to be 'debug' information generated by the dongle. As I write my logfile.txt has a size of 0 kb (as it is being written to whilst I use my dongle to access the internet) and the bkuplogfile.txt is 4168K and contains a list of when I last used my dongle; connections, problems, etc.
Just ignore them - I know they may be big and there may be a way of stopping the dongle producing them, but they do no harm.
Nick