the text pointer can act-up for several reasons.. for example if you're using a custom cursor that has many colours(64bit) more than supported than the os. a friend once had a similar problem when he used vista aero whatsit cursors on an xp pc. so if that's the case, make sure to use the default windows text pointer:
control panel>mouse>pointers>text select>'use default' button.
another reason could be if you're using a laptop, the touchpad sometimes causes this problem if for any reason something moves on it(tiny spider?).. then try this tool called touchfreeze: http://code.google.com/p/touchfreeze/