I connect to Progress via ODBC all the time, so that is not the problem.
Did you use the Select button in the script windows?
Here you can go to the table you want and use the preview tab if there is the data you expect.
Also us preceding load, this makes it easier to controle your data in the script
I your case it should look something like:
SQL SELECT cInitials,
Have a look-see if your ODBC settings are correct - for example, by using your ODBC connection to access this data from Excel. There's sometimes ODBC settings that have to be changed from the default (related to quoted identifiers, nulls/padding, etc), so this should narrow down your issue to either the ODBC connection, or an actual QlikView problem.
It turns out it was a problem with the SQL WIDTH attribtues on the DB fields. I tried to query from Excel and got an actual error back along the lines of: Column cInitials in table PUB.Customers has a value exceeding its max length or precision". As soon as I saw that I remembered the SQL WIDTHs attributes. Increased those, and now it returns the values!