This error can occur when the affected user's Salesforce profile has insufficient permissions on the Documents object. In the reported case, the user had only Read access, which prevented Apsona from creating or updating the document during upload.
To resolve the issue, update the user's Salesforce profile permissions for the Documents object to include Create, Read, Edit, and Delete access, along with the required visibility permissions. After saving the changes, have the user clear the Apsona cache and retry the upload.