Cool Tools Type Mismatch Error

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I am trying to create a set of bi-quadratic curves for a series counter flow branch using the Cool Tools spreadsheet. I have entered all the data, but I am getting a Run Time Error '13': Type Mismatch when I click create regression models.

I did have to modify the entering temp CWST to match the performance data. I didn't think that would affect the curve fit though. Does anyone know how to resolve this error? I'm not familiar enough with the underlying VBA to troubleshoot it very far. I would be glad to send the spreadsheet, but there isn't a way to attach it to this post.

Thanks.