Hi,
If I'm correct - win32com.dll is part of Java installation - Java Communication API and is already present in serial bootloader interface root. From readme.txt I can see that this interface requires Java jre7:
To open this interface:
1.- Double click on Serial_Bootloader_Interface.jar
2.- or In cmd you can use the following:
c:\your_directory\your folder\Java interface>java -jar Serial_Bootloader_interface.jar
3.- or select open with and chose the javaw.exe file from your installed Java run time environment, for instance:
C:\Program Files\Java\jre7\bin\javaw.exe
To use the Bootloader interface simply:
1. Select communication port
2. Select baudrate, the default baudrate is 19200.
3. Select SREC file to send
4. Click download, and the SREC file will be sent line after line.
I can use this interface without any issue on 64bit win10:

Jiri