Hi Bob
Have just downloaded K4 into TRS06 with no problem.Shows up OK.My initial action in this sort of situation,is to delete item and all the custom dependencies and reinstall.
To help,I list the dependencies with their kuids,,just in case your CMP is lying to you and one is missing.
Built in kuids:-
SAR 520 Enginespec 523:51070
Bigsteam interior 523:55901
K27 Whistle 43955:54003
Custom Kuids:-
K4 Bogey 67810:50002
K4 Bogey1 67810:50010
k4 Bogey2 67810:50020
K4 Enginesound 67810:53003
Hope this helps Regards Bruce