Trying to upload a public private key

[#1]

I've been trying for two days to upload a certificate and private key to Apigee but keep getting the following message:

{
  "code": "messaging.config.beans.KeyParseFailure",
  "message": "Failed to parse the Key file : pearsonKey",
  "contexts": [],
  "cause": {
    "message": "Invalid passphrase or invalid rsa key, reason - expecting an rsa key",
    "contexts": []
  }
}

My key pair contains attributes specified at the top like so:

localKeyID: 37 35 34 38 36 36 35 30 30 37 33 39 34
friendlyName: apigee-dev
Key Attributes: <No Attributes>

Any help would be greatly appreciated!