It sounds like you are using tripmaster v2.0 beta. You cant access the setup screen from that program. You can do 2 things if that is the program you are using. If you are using 1.8a then #2 should also work for you
1. Start tripmaster 1.8a on your tomtom, press the lower right hand screen and enter setup.
2. connect your tomtom to your computer, open windows explorer and open the tripmaster file and edit the config.txt file. set units to english. this should work. (don't use the ***)
here is my file:
[Log files parameters]
trackperiod 60
trackdistance 2
trackcourse 45
trackformat kml
tracksaving new
logfilename none
autologging no
records long
[Other parameters]
language english.lng
****units english*****
colorscheme night
gmtoffset -8
geoidfix no 48
maxspeeddisplay yes
maxspeedvalue 0
compass both
coordinates decimal
snapping yes
inclinometer 5
speedlimit 0
speedalarm visual
speedinterval 0 30 45 65 75
alarmfilename /mnt/sdcard/tripmaster/speed_alarm.ogg
processperiod 500
bootstart no
displayaltitude no 30
alarmperiod no 10
accelerometer 0
screenadaptation rider2
[Colors parameters]
topforegroundcolors 0,0,0 255,255,255 204,204,204
bottomforegroundcolors 255,255,255 255,255,255 204,204,204
topbackgroundcolors 255,255,255 0,0,0
bottombackgroundcolors 0,0,128 0,0,128
linescolors 204,204,204 204,204,204
labelcolors 255,0,0 255,255,0
daybackground
nightbackground /mnt/sdcard/tripmaster/images/bgnd_wide_night.bmp
[End]
Hope this works