Help with Index, indirect, and match

I am doing a project for work, and I am dealing with a large file with multiple tabs. I am building a table for a graph that is going to feed off of two data validation lists (B4 and T4). The graph/table is going to pull different information based off B4, which is either YTD or FY, and T4 which is multiple Regions. So I am using Indirect to reference my 2 tabs: SIMPLE_YTD, or SIMPLE_FY. However, I keep getting a #REF! error in my indirect formulas.


Here is the formula I am using: =INDEX(INDIRECT("SIMPLE_"&$B$4),MATCH(VLOOKUP($S$4,$AE$3:$AF$23,2,FALSE),INDIRECT("SIMPLE_"&$B$4),0),MATCH(R16,INDIRECT("SIMPLE_"&$B$4),0))

Am I using the indirect formula Wrong?

Any help would be greatly appreciated, thanks.

Thanks for the prompt response, unfortunately I am dealing with some rather confidential information and can't post the workbook or sheets without getting sued. That being said, Simple_YTD and SIMPLE_FY are both sheets. I am pulling info from these sheets into my table, and I am dealing with lists in both B4 and T4.

Do I have to specify a range (in the indirect formula) within the sheets to tell the formula where to pull the information from?