SSL problem

Hi,

I am trying to start the postmaster with SSL support. -l option is used to start the postmaster to start with ssl
support.when I am trying to start 
with -l option, it searches for server.crt and server.key file. I have bothe files in data directory.
but each time when I am trying to start the postmaster with -l option, I am getting following error

Failed to load private key file (data/server.key): problems getting password

Can anybody please help me in this?
Please help ASAP.

Thanks in advance.
Namrata.