Hello,
so to give you status of our issue.
We were able to export missing business component 
.
But we also exported some interfaces after that and we had some return code 8, due to objects still present in change list on quality system (seems after previous failed transports , the change list was not cleared completley...).
So now we have checked that no objects is present in the change list of quality system and we plan to export again our devs on quality system.
Hope after that no more return code 8 during imports and all devs transported correctly on quality system.
S.N