Hrmm... you could also try going into the Game Menu (the clipboard icon/F2 key) then options and turning off show ship movement lines. I vaguely remember a post in the past on some older Versions of SE4 where range check errors occurred in some systems with this feature turned on.
Edit: A quick search of the forum turned this up
LINK so you might want to try what I suggested above. Hope it helps.
[ October 22, 2003, 03:02: Message edited by: Cyrien ]