From Log: "unable to set private key"

[greenftechn]

Using Zen Cart 1.39d
I am testing the Linkpoint payment module and getting the standard error message in the browser: :
<We apologize for the inconvenience, but we are presently unable to contact the Credit Card company for authorization. Please contact the Store Owner for payment alternatives.>

I check the debug log from the transaction and see:
Jun-21-2010 02:47:12
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Communication Result: 58 - unable to set private key file:

My private key is passphrase protected. Will it work under those conditions, or do I need a non-password-protected private-key file?