problem with cruise control.

I changed the final drive gear box, before there were 4.255 and now 3.666. (I drop the rpm about 700rpm when i was driving 100km/h before)
Now the car travels 2,200 rpm and speed 100km / h in 5 gear.
When i drive in 4gear then is everything OK, but when driving in 5gear the cruise control dont work anymore.
Either may be a conflict in the engine ECU. Engine speed and running speed ratio is false? or ECU modules written restrictions?

I Have a ECU:
Address 01: Engine Labels: 06A-906-032-AJQ.lbl
Control Module Part Number: 06A 906 032 HN
Component and/or Version: 1.8L R4/5VT G03 0002
Software Coding: 11510

What could be causing this, is it to change?

My different gearboxes are:

code:
EAG 5 4WD Golf/Bora '99 62 17 3,647
EAH 5 4WD Golf/Bora '99 72 17 4,235