Error with exporting data to csv using R for a merged query

Hello,

I want to export a query results into CSV file using R scripting, I have used write.csv command line and it worked with tables that sourced data from an excel data source, but I want to use the code with a query that is a result of merging three tables (I merged three imported tables that were sourced from an excel sheet) but when I run the write.csv R script to export the merging query result I get the below error:

Formula.Firewall: Query 'BSC' (step 'Run R script') references other queries or steps, so it may not directly access a data source. Please rebuild this data combination.