When you are logged in to the Folio Builder panel in InDesign CS5 or CS5.5, no content is visible, and the error “svr.unknown” is shown
Uninstall the Folio Producer tools and reinstall them following the instructions on this Help page:
Installing digital publishing tools
If your articles still show spinning wheels (progress bars) and hovering over them with your mouse gives the tool tip "Updating Article," delete the affected articles. Then readd them to the folio.
NOTE: Do not delete the folio that contains the affected articles, just the affected articles.
It is critical to keep the Folio Builder panel in sync with the server-side software that it communicates with. With Folio Builder panel version 1.1.2, server upgrades are disabled the panel if it is not in sync with the service. Users are prompted to install the latest version. However, versions 1.1.1 and earlier did not have this mechanism, so they produce the enigmatic "svr.unknown" error.
For customers using earlier versions of the InDesign Digital Publishing plug-in to maintain compatibility with Viewer applications, this Folio Builder panel-only update doesn't affect that compatibility.