can not open output file

Hi,
I am trying to install a software, when i click on the setup icon, the file opens with 7-zip then from what i see i have no option than extracting files to the destination C:\Program Files (x86)\

after completing the 100% of the extraction, a window appear and tells me:

# Message
0 can not open output file c://Program Files (x86)\x64\ACA\ACA.msi
1 can not open output file c://Program Files (x86)\x64\ACA\SetupRes\eval.msi
.
.
.
3200 can not open output file c://Program Files (x86)\x64\ACA\...

(3200 errors)

Computers is not my profession, thats why i hope u can help me!
Thank u in advance for ur reply

btw i have the vista home prem 64-bit operating system. thank u

thank u, ur replies helped me a lot

Try using winrar and then right click and repair archive.