Before you can view the ASM skymaps, you must do the following things on your machine so that netscape will properly display them:

In your personal netscape configuration directory (probably your home directory ~) add the following lines to the files 

 
   .mime.types :   application/octet-stream fit fits FIT FITS
                   image/x-fits            fts     fits    fit
 
   .mailcap :      image/x-fits; saoimage -quiet -fits %s

Also confirm that you have a version of saoimage in your path that will calculate RA and DEC of a position within the map pointed to with the mouse.