Installation issue on Windows Vista 64 bit

When I tried to install a software on Windows Vista 64 bit, I received an error 1603 during installation and installation failed.
It was installed sucessfully on Windows Xp and other versions. Could anyone tell me the reason and solution to this problem?
Do we need some changes in Install Shield?

What software package?
look in your error logs;
Start --> right click on computer, select manage
Click on event viewer
Look at errors and warning.
This will give you an idea what happened.
List your system specs.

With this info we will be able to give you more of an idea whatis happening.

Full instructions from microsoft on how to get around this are found here;

You receive an "error 1603: A fatal error occurred during installation" error message when you try to install a Windows Installer package

Well. the event log didn't help much.
I am using Dell Inspiron Laptop with Intel Core 2 duo T7500.
OS- Windows Vista Home Basic 64 bit edition

The software package is nothing but Drivers for a communication adapter using USB and serial port. The drivers are used for communication with Device(Adapter).

Let me know if you need further details.

Tell me what the adaptor is.
Have you clicked on the link I provided as it tells you what the error is?

Yes, I tried with that link, but problem still persists.
Our adaptor is used for communication on CAN based networks in Automotive industry. It communicates with PC via USB and serial port and exchange data with devices on CAN network. We develop drivers for it. This error occured during installation of these drivers setup.
It is installed successfully on other versions except 64 bit vista.

I observed during installation that it fails while it is writing system registry values. See if it helps in analysis.

It looks like a privalige error. Are you installing the software as administrator?
What is CAN based networks?

If you are using a usb modem you will run into trouble, I do not know if vista supports usb modems.

Have you tried creating a separate file to modify the registry and using two different files as drivers, one for the os and one for the registry edit.

Thanks for the reply.
Yes I logged in as Administrator.
Well we can leave the CAN part. You can visualize adaptor to be a device that receives data through Serial or USB port, processes the data and puts it onto CAN network. So drivers for USB/serial need to be installed.
Its not a USB modem.
I tried to manually copy driver on system drive and connected my device on USB. It said "cannot load drivers as the drivers are missing or corrupt".

Vista is not allowing to modify/delete the registry key manually.
As far as creating file for editing registry is concerned, I am not aware of it. Please let me know how to do that.