Your settings file may have become corrupted - you will need to delete it (create a backup first).
Please navigate to:
C:\Documents and Settings\<Your user name>\Local Settings\Application Data\Pico Technology\
You may need to enable the option to view hidden files and folders in Windows.
Find the folder with the long alphanumeric name containing the plw.ini and Recorder.pls files, create a backup and delete them.
Next, restart PicoLog.
Hope this helps.