For a manual edit of that line you would use the BCD editor included in Vista itself. For changing the default OS or entry based settings those are found in the "Change Settings" section of the EasyBCD tool.
bcdedit isn't a program that you "open" like you do with EasyBCD (ie. you execute it with switches and parameters from the command prompt). If it were, there wouldn't be a purpose for EasyBCD. EasyBCD can do simple edits to the path for changing the partition only. If the boot files are in another folder than the defaults, you'll either need to adjust to them or learn how to use bcdedit.
EasyBCD itself was written to work with the default location of the winload.exe file as seen there in sub folder of the Windows directory. That's where the Vista installer installs that file in order to see Windows run. If you edit the BCD store and try pointing to that same file copied elsewhere it won't see Windows load.
For seeing another OS loaded you wouldn't even change that but use the options to select the partition/drive where the other OS's boot loader is located if not already copied to the root of the Vista primary. But you will to explain what you are trying to do there with a change of the boot path.
You replaced one edtition with another there. To see both load you would need to set up a dual boot between the two editions probably seeing each on a separate drive since Vista wants the first primary by default.
You can't simply change to an archived set of folders since that was for saving files following an upgrade to Vista or change of editions which you saw there. Like Makaveli213 pointed out you would have to roll back to Home Premium first.