OK, here is some more information.

I used INPA/Ediabas to read the car's ECU and here is what I found.

ECU: EHC
JobStatus: OK
Variant: EHC

8 Regelzeit, heben
Error frequency: 31
HoehenStand noehere seite 221.00mm
Stand

Now, is it possible that this is the result of me lifting up the car the day this started, to check something behind the wheel? I lifted the car up enough to remove the wheel, reinstalled it, then lowered it (albeit a little harshly, I was not familiar with that trolley jack so when I opened its valve the car fell instantly).

Advice will be really welcome here!!!

check the height sensors on the side that you did not lift, and the other side - see if the sensor's elbow is inverted, or, if the sensor is disconnected...

Thanks man, I appreciate it. I'll take the car to a local shop tomorrow and have it checked.

you can do it yourself - just look under the car and see how those sensors look...

Well, the sensors looked OK, so I took the car to the shop. It's going in tomorrow for some new suspension parts, so we'll also run the diagnostics to see what's wrong.

Well, the mechanic changed a fuse and reset the suspension, and everything went back to normal, except that he said thre is a small leak somewhere. Then they checked and double-checked everything but couldn't find any leak. They tighten the nut of the tube going from the compressor to the left air canister and another nut on the air pump and they told me to watch it.

So I guess all is well.

On a side note,we changed the two control arms at the front, the bushings of the other control arms, two rings at the pipe going from the intercooler to the inlet manifold, plus a rear antiroll bar link, we adjusted the lights, all for $470. Service is cheap in Ukraine!

so, while in ukraine, what else have you done? did you do any programming changes?

Unfortunately no.

However, when we passed Bulgaria, I visited the local BMW distributor, in order to get a new exhaust manifold (the existing one was cracked) and asked them to program the driver's seat to move to a predefined position according to the remote used to unlock the car. They told me it is not possible, probably due to the non-BMW radio I have (same reason was given to me by the Greek distributor too).

This is becoming frustrating, since it is the only thing I would like to have on the car and I do not have it. The frustration arises from the fact that my car doesn't show consistent information with the various programs. For example, INPA/EDIABAS shows a Seat Memory module (and actually shows that the car is programmed to move the seat, when the door is opened, not when the car is unlocked), while NCSExpert doesn't show a Seat Memory module. Also, the parameter that defines how the seat is moved (Aut_Sitzsomething) doesn't show in my Key/Memory page of NCSExpert.

I checked our son's new X5, and everything appears correct. NCSExpert recognizes a Seat Memory module, and the parameter is shown in Key/Memory page, but he has only one key, so we can not test if his seat moves correctly. I am wondering, if someone has removed the Seat Module from my car, before I bought it.

Check Fuse #80 in the Rear Hatch Fuse Box and see if it is blown (30AMP for the Air Compressor)

If it is blown, that is your problem.

That was fixed. Thanks!