Having trouble reading excel file with the OpenXML sdk

I have a function that reads from an excel file and stores the results in a DataSet. I have another function that writes to an excel file. When I try to read from a regular human-generated excel file, the excel reading function returns a blank DataSet, but when I read from the excel file generated by the writing function, it works perfectly fine. The function then will not work on a regular generated excel file, even when I just copy and paste the contents of the function generated excel file. I finally tracked it down to this, but I have no idea where to go from here. Is there something wrong with my code?

create dynamic table in powerpoint using openXML with c# and ASP.net

I have used these links and got a working code where I can use a template report(containing placeolders) and generate new PPTX report with data I get from database. I have 4 more placeholders where I need to populate 4 different data tables. Currently I am using that template to create new slide and replacing placeholder for text but for tables I couldn’t figure out. I am able to generate the table using below code but not in placeholder’s location. Table always appear in center of screen.