JDBC Driver

Hello there.
I am new to PostgreSQL and having a big problem with the JDBC driver.
I have downloaded it from http://jdbc.postgresql.org/download.html
I tried both jdbc7.1-1.2.jar and jdbc7.0-1.2.jar and they are both unusable.
Neither jar nor Winzip can't open them. Nor could I open them with java -jar
command.
I tried to download them several times from various machines with the same
result.
Java gives me following exception:
Exception in thread "main" java.util.zip.ZipException: invalid CEN header
(bad signature)
        at java.util.zip.ZipFile.open(Native Method)
        at java.util.zip.ZipFile.<init>(Unknown Source)
        at java.util.jar.JarFile.<init>(Unknown Source)
        at java.util.jar.JarFile.<init>(Unknown Source)
Winzip gives an error: Start of central directory not found. Zip file
corrupt.

I found this discussion on the mailing list archive and desided to drop you
a line.
Can you explain what is wrong and where I can get a working driver. I am
building just a PC client
so I don't want complete distribution, neither do I have time to build it
from source.

Thank you very much and please respond ASAP.