If you ever encounter an issue logging into Helper that is identified as a "Database" issue, or if there are irreconcilable synchronization issues, you may need to reset your Helper Database. This article explains how to do just that.
First, make sure that Helper isn't running. Exit it, if it is.
Next, navigate to your your PPU Helper Databased folder. It's going to be located on your Helper PC in a file path much like the example below, but with your specific PC and Windows user names in the indicated spaces:
C:\Users\[YOUR_WINDOWS_USERNAME]\AppData\Local\Photo Party Upload Helper\DB
In that folder, the Helper Database file (ending in ".sdf") We're not deleting it, just renaming it so that you still have access to it if, for any reason, you should find you need its data.
Right-click on the database file and select "Rename."
Now, after the ".sdf" add ".old" and click elsewhere to save it. You may see warnings about renaming the file, but agree however is necessary to proceed.
Now, re-launch the Helper.
A new database will automatically be created in the folder, and hopefully this will resolve your issue moving forward. If not, please let us know.