Table dataset to Report Viewer Table

I’m trying to link data from a table’s dataset to a table in Report Viewer (to be saved as PDF and/or emailed). I’ve created a custom dataset for the report viewer component, and everything populates correctly. However, when attempting to link some of the keys (type float with attribute suffix “%” in cell update), I get “Error Parsing KeyChain” warning and “” as the value?

Solved, no special characters in table headers are allowed.

Please acquaint us with what you did i.e the script you use etc. Thank you