SSL install problem - "key value mismatch" (but they do match?)

So I've been sent a new public cert to install on a server (.crt file). Done. Restart apache - "FAILED".

Error message:

[Tue Jan 11 12:51:37 2011] [error] Unable to configure RSA server private key 
[Tue Jan 11 12:51:37 2011] [error] SSL Library Error: 185073780 error:0B080074:
x509 certificate routines:X509_check_private_key:key values mismatch

I've checked the key values:

openssl rsa -noout -modulus -in server.key | openssl md5
openssl x509 -noout -modulus -in server.crt | openssl md5

and they DO match.

I've checked the paths in my ssl.conf file, and they ARE pointing to the correct files.

If I reinstate the old (expired) cert file, apache starts up ok, so it definitely doesn't like something about the new one.

It's a GeoTrust QuickSSL, and it came with an "intermediate.crt" that I'm supposed to use in place of the the "ca-bundle.crt" file that I was using before

SSLCertificateFile /etc/pki/tls/certs/www.domain.com.crt
SSLCertificateKeyFile /etc/pki/tls/private/www.domain.com.key
SSLCACertificateFile /etc/pki/tls/certs/intermediate.crt

Any ideas what I might be doing wrong? Any more info you need?

Thanks!