Hi Laura,
Not sure what is causing this but the Win8 box may be using a different version of Office and so that means you may be importing with different versions of XLS(X), even as CSV files.

I wouldn't chase the "why this is happening" as we have found a lot of inconsistency with Imports in Adagio between modules and versions of XLS. Rather, change the import template to use the default for both Win7 and Win8 boxes.

Brian