Hi Evan,
Change:

while( defined ( my @row = $sth->fetchrow_array ) ) {
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to:

while( my @row = $sth->fetchrow_array ) {
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and an endless loop problem is fixed.
I think the other problem is your peculiar choice of quote_char.
I found that specifying the general quote char on DBI connection options makes the error go away. As you probably know, this is a general setting, not per table/csv handle.

my $dbh = DBI->connect('DBI:CSV:f_dir=.;csv_quote_char=~;')  or die ..
+.
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I didn't have time to investigate on this one, though it would be interesting to do.