When you import the data from Excel, you need to tell SAS that the variable (or column) names are in the first row of the Excel file. Otherwise, SAS thinks the first row of Excel contains data (and it is not data) and so the variables all show up as character to account for the column name in the first row. You can't create correlations of character strings.
I am not familiar enough with SAS On Demand to explain exactly how to do this, but you need to look for options in the Import process, and then select the correct one to treat the first row of the Excel file as containing column names.
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Paige Miller