If you see this error when running a Report or an analysis in Summaries, this usually indicates that your storage has become corrupted. Although this is rare, this can happen due to a variety of causes, including the hard drive that the storages reside on running out of free space, the software crashing during import, or the storage being moved while the software is importing data to it.
You can attempt to repair the storage, although unfortunately not all errors are repairable. To repair the storage, go to Storages and right-click the name of your storage then click Properties. Go to the Diagnostic tab, and click the Repair Storage button. If the storage is very large the repair could take some time.
After the repair has completed, try running your report or analysis again. If you continue to have errors your best option is to create a new storage with a different storage name, and reimport your data.