Yes, this is a bizarre result that occurs when Word connects to the .csv
file using ODBC. I don't know why exactly, but I think ODBC decides that
some columns are "numeric" and changes e.g. "F1" to 1.

You may have been unaware that Word was connecting using ODBC, or may not
know what ODBC is. It's just one of the methods that Word can use to connect
to data sources. In the case of text and csv files, Word may use either ODBC
or its own internal "Text converter" depending on various factors. In Word
2002/2003 it can use another thing, OLEDB, too.

My guess is that you're using Word 97/2000 in which you can probably fix
this by going into "Open Data Source" again, checking Select method, selting
your .csv and clicking the Open button. You should then see an additional
dialog box called "Confirm Data Source. In there, select "Text Files
(*.txt)" and click the OK button. If you don't see the Text files option,
check the Show all box.

(If you happen to be using Word 2002 or later, you have to check Word
Tools|Options|General|"Confirm conversion at open", then go into Select Data
Source and follow approximately the same procedure as above.

Peter Jamieson