Symantec Antivirus Corporate Edition Doesn't Install in Windows Vista

Hi guys!
I have purchased Symantec Antivirus CE for my office. At my office there are some Windows XP computers and some Windows Vista. On windows XP, everything works fine, but in Vista it doesn't install... What can i do to install it in Vista?
Help Guys

All the softwares have different packages and different versions for all operating system. You might have purchased the windows xp version which won't work on Window Vista. Like wise you won't be able to install Vista version of your Antivirus on Windows XP.
All the best!

I understand... what i mean to say is, i installed Vista version of Symantec Antivirus on my Vista Computers, but still it doesn't install. I have bought symantec antivirus for Vista SP1. but still it doesn't work...! Please help!

Make sure you're vista versions match too, dont try to install 32bit antivirus edition on windows vista 64bit...
This matching must be done too...
Verify and cross verify your windows and antivirus edition and purchase an appropriate edition of Symantec antivirus.
All the best!

I don't understand the concept of 32bit, 64bit, x64 and x86...
I guess i screwed something here... Any help??
My Vista is x64 i guess it is 64 bit but my antivirus box states for windows vista x86. What is that?

x64 - 64bit
x86 - 32 bit

32bit is known as x86 because the core family was of 80286...!
All the best!