[Urgent] Communication error: when using paypal with ecommerce

I setup paypal and ecomerce package on my site for selling some non-shippable goods. I setup the paypal account and put its cert_key_pem.txt file at /home/abc/cert/cert_key_pem.txt . The website is located at /home/abc/public_html/ folder. I put the correct api information received from paypal.com at admin/settings/paypalpro. But trying to purchase something it gives error:

Communication error. Failed to connect to the authentication server. Please try again later.
(libcurl error #35: SSL: error:14094418:SSL routines:func(148):reason(1048))

I have curl at /usr/bin/curl and using "curl binary" option in setting.

I found out the libcurl error#35 meaning at http://curl.mirrors.cyberservers.net/libcurl/c/libcurl-errors.html , it says..

" CURLE_SSL_CONNECT_ERROR (35)
A problem occurred somewhere in the SSL/TLS handshake. You really want the error buffer and read the message there as it pinpoints the problem slightly more. Could be certificates (file formats, paths, permissions), passwords, and others. "

But as far as i can understand i gave all the correct info of certificate path..etc..

@ paypal_framework:

PayPal email: Blank (dont know what to write)
IPN reply method: Curl Binary
Curl binary: /usr/bin/curl (checked on server as well, this is correct)
Reply POST address: https://www.paypal.com/cgi-bin/webscr
Enable verification queueing : not checked

@ paypalpro:

Use secure SSL connection: Enabled

Express Checkout URL: https://www.sandbox.paypal.com/cgi-bin/webscr

API Server URL: https://api.sandbox.paypal.com/2.0/

PayPal Web Services API Account Name: given at paypal.com api Certificate information

PayPal Web Services API Account Password: given below of above mentioned api user nameat paypal.com

PayPal Digital Certificate: /home/abc/cert/cert_key_pem.txt [as downloaded from paypal.com and put on server]

Successful payment URL: store/transaction/view/%txnid

please let me know whats the problem? I tried to disable the ssl connection at paypalpro but still same error.

-rafi