My situation was a little different. The solution was to strip the .pem from everything outside of the CERTIFICATE and PRIVATE KEY sections and to invert the order which they appeared. After converting from pfx to pem file, the certificate looked like this:
Bag Attributes
localKeyID: ...
issuer=...
-----BEGIN CERTIFICATE-----
...
-----END CERTIFICATE-----
Bag Attributes
more garbage...
-----BEGIN PRIVATE KEY-----
...
-----END PRIVATE KEY-----
After correcting the file, it was just:
-----BEGIN PRIVATE KEY-----
...
-----END PRIVATE KEY-----
-----BEGIN CERTIFICATE-----
...
-----END CERTIFICATE-----