Open SSL's X509_load_crl_file function returns the number of revoked certificates loaded from the CRL file but when libcurl calls X509_load_crl_file it expects it to always return 1. If 1 is not returned then the SSL connection cannot be made.
Using libcurl version: 7.19.6.
openssl version: 0.9.8g-10.1ubuntu2.5
Patch to fix call to X509_load_crl_file
Thanks for the report, this problem is now fixed in CVS!