Hi Axel,

It sounds to me as if you're suffering from a Y2K bug involving
artificial satellites, described here:

http://www.projectpluto.com/update7b.htm#y2k_satellites

As is mentioned there, if you get the current software, the problem
will go away (as will one or two other Y2K related issues.)

As Masaki Kouda noted, you can use 'Ctrl-B' (or, equivalently,
"Go To... Generic Object") to find satellites. In either case, you can
use "Mir", or "Mir Comp", etc. You just have to make sure that you
provide enough letters that Guide can distinguish the object.

-- Bill