In the U.S., the 1999 323i was an E46 - with or without the Sport Package.
That was the last year for E36 2 door coupes & convertibles.

Tom K.

The standard OBD-II codes do not vary by manufacturer or model.  One
website says SAE code P0455 is "Evaporative Emission Control System Leak
Detected (gross leak)."  I think P1250 might be a manufacturer-specific
code, but the gummint's CFR website is not responding so I can't
retrieve the list.  However, if they both appeared at the same time I'd
try to fix the P0455 and see whether the P1250 went away, too.

Oh, by the way, make sure the gas cap has an undamaged seal and seat,
and that it's tight.  That's often the reason for EEC leaks.

Note: The CFR (all of it!) is at

http://www.access.gpo.gov/nara/cfr/cfr-table-search.html

JRE

I doubt the codes could be wrong. You can search the Web for <OBD II
DIAGNOSTIC CODES> (without the < or the >) and find several references for
the codes and what they mean.

All Codes in the range of P0420 to P0459 deal with the Evaporative Emissions
Control System -- the system that prevents gas fumes from escaping into the
atmosphere -- and the vast majority of the problems in this area are rooted
in problems with the gas cap. You could, of course, have cracked and
splitting vacuum hoses or that sort of thing.

Forgive me, but my weak recollection on the P0120 code is something related
to the O2 Sensor.