Gopher, are you by any chance *double-clicking* the map to target or move your units? This might cause the behaviour you're seeing. Also, are you using an optical mouse?
A minor solution to your problem would be to learn using the keyboard T, F and N/P to target units, but this would not solve the movement issue of course.
Idea for the future - being able to use the keyboard for movement would be *great*, i.e. for example the numpad to move one hex at a time
Stian