MySQL 5.5.8 SSL error: Unable to get private key from 'server-key.pem' (no replies)

Background: running on Windows. Cert and key files made the same way work on Apache 2.2.15, but MySQL Server 5.5.8 refuses to enable SSL with the following error during service start:

SSL error: Unable to get private key from 'C:/ProgramData/MySQL/server-key.pem'
101229 15:21:28 [Warning] Failed to setup SSL
101229 15:21:28 [Warning] SSL error: Unable to get private key

The my.ini config file looks like this:

ssl = On
ssl-ca = "C:/ProgramData/MySQL/ca-cert.pem"
ssl-cert = "C:/ProgramData/MySQL/server-cert.pem"
ssl-key = "C:/ProgramData/MySQL/server-key.pem"

The cert and key files were converted from a PFX file using the Openssl command-line tool with the following sequence:

1. openssl pkcs12 -in "combined-cert.pfx" -out "combined-cert.pem" -clcerts -nodes
2. openssl x509 -inform PEM -outform PEM -in "combined-cert.pem" -out "server-cert.pem"
3. openssl pkey -inform PEM -outform PEM -in "combined-cert.pem" -out "server-key.pem"

As stated above, these work fine on Apache and verify using the Openssl command line tool.

Any ideas, please?