If I'm understand the question correctly I believe he's trying to run two different versions of ADB at the same time. If my assumption is correct then here is what you'd want to do.
Lets assume you have adb.1.0.29.exe and adb.1.0.39.exe on the root of the c: drive which were renamed from the adb.exe from the different versions of platform-tools SDK versions they were supplied in.
To run the ADB version contained within adb.1.0.29.exe all you have to do is what the linked articles say BUT be sure to call the proper exe for that version. I used these adb version names as examples. You can name the adb.exe whatever you want.
So you can call adb commands with different versions as follows,
c:\adb.1.0.29.exe -s serial_of_device adb_command
or
c:\adb.1.0.23.exe -s serial_of_device adb_command
Cheers,
-Rob