adb.exe android gives me error with su
I got a tip from XDA dev's under Android-General Developing: give the custom ROM a new name by renaming "update.zip" on the SD Card. Under CWM, pick this "update.zip" under Update setting.

This was tested with Moto Defy+ 2.3.6 stock ROM and HTC One V GSM with a Sense 5.0 custom ROM when I tried to install MIUI 5.