Many thanks to a Chilkat customer that helped solve his own problem. Here is a bit of useful information:
(from somewhere in the depths of the Microsoft MSDN web site:)
"When you move or copy an X.509 certificate from one certificate store to another, do not use the Copy or Cut command in Microsoft Management Console (MMC) Certificates snap-in. Instead, use the Certificates snap-in to export the certificate from one certificate store and then import the certificate into the destination certificate store.When you copy or cut a certificate from a certificate store and then paste it into another, WSE will not have sufficient permissions to the file. The MMC does not move the file associated with the X.509 certificate. So, even if you grant read permissions on the file to the account under which WSE is running, that account may not have access to the path to the file. To avoid this issue, export the file from one certificate store and import it into the other."