The factory default address of MBR3 device will not change until you change it manually. So you may not need to worry about it.
The Kitprog present on the MBR3 kit might have gone into bootloader mode. To recover the kitprog back to the programmer mode you have to upgrade the Kitprog firmware. For this please do the following steps.
1) Connect the kit to the PC.
2) Open PSoC Programmer and close all other Cypress software like PSoC Programmer, Bridge control panel.
3) Go to Utilities tab of PSoC Programmer and Click on Upgrade firmware. Wait until the Kitprog is reconfigured.
4) Close the programmer and now open the Ez-Click and try configuring once.
Check this once and update the thread whether it is working or not.