diff --git a/TablePlugin/data/System/TablePlugin.txt b/TablePlugin/data/System/TablePlugin.txt
index 3b7785043b..1ad06d330d 100644
--- a/TablePlugin/data/System/TablePlugin.txt
+++ b/TablePlugin/data/System/TablePlugin.txt
@@ -116,6 +116,7 @@ Information for programmers.
 |  Version: | %$VERSION% |
 |  Release: | %$RELEASE% |
 |  Change History: | <!-- specify latest version first -->&nbsp; |
+|  03 Sep 2009 | 1.041: Kenneth Lavrsen: Fix for crash when cell contains the number 0. Allow sorting of negative numbers even when suffixed with unit. Treat whitespace as zero if pure numerical context. |
 |  02 Sep 2009 | 1.040: Kenneth Lavrsen: Fixed the fix of parsing date-time columns so that plain numbers are not interpreted as dates causing wrong sorting |
 |  03 Jun 2009 | 1.039: Michael Daum: fixed parsing date-time columns |
 |  19 Apr 2009 | 1.038: Removed support for settings in the plugin topic which is a bad idea anyway as they get overwritten at each Foswiki upgrade. Define the global settings in <nop>%USERSWEB%.SitePreferences instead. <br />Fixed an issue where TablePlugin produced invalid css if no 'px' or '%' is passed in a size parameter. <br />Small refactoring in style attribute handling. |
diff --git a/TablePlugin/lib/Foswiki/Plugins/TablePlugin.pm b/TablePlugin/lib/Foswiki/Plugins/TablePlugin.pm
index 4543b0b705..e0cd42719c 100644
--- a/TablePlugin/lib/Foswiki/Plugins/TablePlugin.pm
+++ b/TablePlugin/lib/Foswiki/Plugins/TablePlugin.pm
@@ -32,7 +32,7 @@ use Foswiki::Plugins ();    # For the API version
 use vars qw( $topic $installWeb $initialised );
 
 our $VERSION = '$Rev$';
-our $RELEASE = '1.040';
+our $RELEASE = '1.041';
 our $SHORTDESCRIPTION =
   'Control attributes of tables and sorting of table columns';
 our $NO_PREFS_IN_TOPIC = 1;
diff --git a/TablePlugin/lib/Foswiki/Plugins/TablePlugin/Core.pm b/TablePlugin/lib/Foswiki/Plugins/TablePlugin/Core.pm
index ffbfbc3324..b96387b8ff 100644
--- a/TablePlugin/lib/Foswiki/Plugins/TablePlugin/Core.pm
+++ b/TablePlugin/lib/Foswiki/Plugins/TablePlugin/Core.pm
@@ -507,12 +507,12 @@ sub _convertToNumberAndDate {
         return (0, 0);
     } 
 
-    my $num = 0;
-    my $date = 0;
+    my $num = undef;
+    my $date = undef;
 
     # Unless the table cell is a pure number
     # we test if it is a date.    
-    if ( $text =~ /^\s*([0-9]+)(\.[0-9]+)?\s*$/ ) {
+    if ( $text =~ /^\s*-?[0-9]+(\.[0-9]+)?\s*$/ ) {
         $num = $text;
     }
     else {
@@ -525,7 +525,7 @@ sub _convertToNumberAndDate {
 
     unless ($date) {
         $date = undef;
-        if ( $text =~ /^\s*([0-9]+)(\.[0-9]+)?/ ) {
+        if ( $text =~ /^\s*(-?[0-9]+)(\.[0-9]+)?/ ) {
             # for example for attachment sizes: 1.1 K
             # but also for other strings that start with a number
             my $num1 = $1 || 0;
@@ -739,7 +739,7 @@ sub _guessColumnType {
     my $date          = '';
     my $columnIsValid = 0;
     foreach my $row (@curTable) {
-        next if ( !$row->[$col]->{text} );
+        next if ( $row->[$col]->{text} =~ /^\s*$/ );
 
         # else
         $columnIsValid = 1;