A bug in the processor of my TP 700

[Waldemar Puszkarz <puszkarz@cosm.sc.edu>]

Here is something that worries me and I suspect that it suggests 
a bug in the processor 486SLC of my TP 700. As I am not entirely certain
if I do everything correct, I would appreciate your advice.

Facts:

1. It says "illegal function call in the module JPSTPHN at address 
05BD:0598" and terminates the program. (JPSTPHN is a lovely program to
simulate eclipse phenomena in the system of Galilean Jupiter's satellites 
that I downloaded from the Internet.) Now, the problem is that the same 
program runs very well on a desktop IBM PS/2 57 SX that I have an access
to. 

2. It locks up when running another program right at the start. The
program runs without any problem on the mentioned desktop.

3. In a demo of DERIVE (software for symbolic computations) displays
distorted highlighted boxes and scrambles slightly a text within those
boxes. Also, it happened to terminate the demo saying "Error!Return with
no preceding call" but it did only once, I could not make it repeat this,
so it looks like it sometimes acts sort of randomly. No problem with this
on the desktop.

4. It has graphics problems with yet another program, leaving a trail of
lines when the program is finished. The lines disappear after the screen
is scrolled down. Nothing like that shows up on the desktop.

It definitely has graphics problems but it does run a number of other
programs very well including those that use graphics extensively,
which leaves me baffled.

I would greatly appreciate your opinion about this. I have no
documentation about this machine as I bought it used, without any manuals. 
I am trying to get ones.

TIA. Waldemar