Here is the SQL statement that returns nothing:
SELECT tbl_CNVs.[Chr:Pos:Gene], tbl_CNVs.Run_Name, tbl_CNVs.Sample1_Name, tbl_CNVs.S1_Sample_Type, tbl_CNVs.S1_Cellularity, tbl_CNVs.[S1_5%_CI], tbl_CNVs.[S1_95%_CI], tbl_CNVs.S1_Raw_CN, ([S1_Raw_CN]-2*(1-[S1_Cellularity]))/[S1_Raw_CN] AS CN
FROM...