That error indicates file corruption. If you're running the database directly from a USB flash drive, it is most likely because the USB drive was removed without first exiting AWdb and then using the correct technique in Windows to shut down the device.
Did you try running the Repair utility? From the login screen, click the Utilities button and then select the option to run the REPAIR utility immediately after logging in.
If this does not fix the problem, you may need to restore your last backup. (I do hope you have been running the built-in backup utility each week after you have completed your data-entry after club night.)
