GnuPG decryption problem

[m.aflakparast at ut.ac.ir]

I need to decrypt .gz.gpg files (e.g. 70195_C1_WTCCCT442627.CEL.gz.gpg).
I have the encryption key(passphrase).
I used Gnp4win and ran into this error:
     "bad session key"
Then I downloaded gnupg-1.4.9 for windows from the following link:

http://techgenie.com/latest/how-to-install-gnupg-1-4-9-on-windows-xp-vista-and-7/

I followed the instructions and installed.
Now, when I use the full path to the gpg program (gpg.exe)
in the command line, and enter the following command:

gpg --decrypt "myfile.gpg"

I am asked a passphrase, but the problem is that it is not possible to
write any thing in fron of the statement" Enter Passphrase:", e.i.
whatever you type, nothing appears on the screen!

I will appreciate it if you CC me your solution.

Best regards,
Mehran Aflakparast


Your prompt attention and kind reply will be highly appreciated.

Best regards,
Mehran Aflakparast