There is some history of Windows XP (and other versions?) losing a window off the screen. It sounds like acote's solution offers the best approach.
As an alternative, if you have the capability, INCREASE the screen resolution to the MAXIMUM POSSIBLE. That might bring the missing TEMPO window into view so that it can be moved back into the regular Encore viewing area. Then, simply return the screen resolution back to its earlier value.
"We have met the enemy and he is us."
Encore 188.8.131.526 Win, Windows 7 Pro (7 Home on laptop, XP on an old desktop).
Been using Encore (Rhapsody, Passport) since 1992