Period Comparison template question - Tried to install and have error message

I have a question about the Period Comparison template from Tiller Community Solutions.

I installed the template and i am having a error message:

Error Function UNARY_MINUS parameter 1 expects number values. But ‘Net Available’ is a text and cannot be coerced to a number.

I tried to restore and it just spins without any resolution.

What should i check or do to resolve this issue ? Thanks