Cognos Servlet Gateway Error: CAM-CRP-0157

I am making some updates to the Servlet Gateway, while another team member was making updates to the Dispatcher. He made his updates first, and then I deployed a new version of my Gateway, which gave users the following error after they entered their username & password:

<errorDetail><errorCode>-13</errorCode><errorMessage>CAM-CRP-0157 Unable to complete a call to the cryptographic provider’s unwrap function.</errorMessage><errorStack><errorCode>-13</errorCode><errorMessage>CAM-CRP-0285 Unable to find an appropriate Common Symmetric Key (CSK) to decrypt the data.</errorMessage></errorStack></errorDetail>

We solved this problem by following the steps in this link:

Keep in mind that some of the items you are deleting are files, and some are directories.

We have no flippin’ idea how this problem occurred, and we will probably not look too hard into it unless it happens again.
These types of rogue errors with no good explanation occur too frequently in Cognos.