Strange debug behavior (bug?)

[fork]

For some reason, if I set debug_on_error (1), I get a keyboard stop in a system
function that works just fine.  Running windows build 3.2.4.  See below (forgive
my two line prompt...)

Any ideas?  Any way to give a dump of the various options I might have set
leading to this, like silent_functions(1) etc?

~:1
$ debug_on_error (0)
~:2
$ Params1 = fc_import('GMA2006_test_M/');
warning: Unknown script.txt parameter and value: "BLAH", 
"InputData\FooBlah.txt".

Y:\Projects\Forecasting\WIPA:4
$ debug_on_interrupt (0)
Y:\Projects\Forecasting\WIPA:5
$ debug_on_error (1)
Y:\Projects\Forecasting\WIPA:6
$ clear Params1
Y:\Projects\Forecasting\WIPA:7
$ Params1 = fc_import('GMA2006_test_M/');
keyboard: stopped in
C:\Octave\3.2.4_gcc-4.4.0\share\octave\3.2.4\m\strings\str2num.m
%% CTRL-C HERE
Y:\Projects\Forecasting\WIPA:7
$

Y:\Projects\Forecasting\WIPA:7
$ str2num ('4')
ans =  4
Y:\Projects\Forecasting\WIPA:8
$ str2num ('4b')
ans = [](0x0)
Y:\Projects\Forecasting\WIPA:9
$

Tx!