diff --git a/ChangeLog b/ChangeLog
index e00779233..9cc24ef9f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,13 @@
 2007-10-23  Wolfgang Sourdeau  <wsourdeau@inverse.ca>
 
+	* SoObjects/SOGo/NSArray+Utilities.m
+	([NSArray -stringsWithFormat:format]): replace instances of NSNull
+	with empty strings.
+
+	* SoObjects/SOGo/NSDictionary+Utilities.m ([NSDictionary
+	-keysWithFormat:keyFormat]): replace instances of NSNull with
+	empty strings.
+
 	* SoObjects/Contacts/SOGoContactLDAPFolder.m: if "displayName" is
 	empty, use "c_cn" instead.
 
diff --git a/SoObjects/SOGo/NSArray+Utilities.m b/SoObjects/SOGo/NSArray+Utilities.m
index 4845b33df..3f5a78b5a 100644
--- a/SoObjects/SOGo/NSArray+Utilities.m
+++ b/SoObjects/SOGo/NSArray+Utilities.m
@@ -20,6 +20,7 @@
  * Boston, MA 02111-1307, USA.
  */
 
+#import <Foundation/NSNull.h>
 #import <Foundation/NSString.h>
 
 #import "NSArray+Utilities.h"
@@ -38,8 +39,11 @@
   currentObject = [objects nextObject];
   while (currentObject)
     {
-      [formattedStrings
-        addObject: [NSString stringWithFormat: format, currentObject]];
+      if ([currentObject isKindOfClass: [NSNull class]])
+	[formattedStrings addObject: @""];
+      else
+	[formattedStrings
+	  addObject: [NSString stringWithFormat: format, currentObject]];
       currentObject = [objects nextObject];
     }
 
diff --git a/SoObjects/SOGo/NSDictionary+Utilities.m b/SoObjects/SOGo/NSDictionary+Utilities.m
index 666aef023..485b9dfb2 100644
--- a/SoObjects/SOGo/NSDictionary+Utilities.m
+++ b/SoObjects/SOGo/NSDictionary+Utilities.m
@@ -22,6 +22,7 @@
 
 #import <Foundation/NSArray.h>
 #import <Foundation/NSData.h>
+#import <Foundation/NSNull.h>
 #import <Foundation/NSString.h>
 
 #import "NSArray+Utilities.h"
@@ -89,8 +90,12 @@
   for (count = 0; count < max; count++)
     {
       value = [self objectForKey: [allKeys objectAtIndex: count]];
-      [keysWithFormat replaceString: [keys objectAtIndex: count]
-		      withString: [value description]];
+      if ([value isKindOfClass: [NSNull class]])
+	[keysWithFormat replaceString: [keys objectAtIndex: count]
+			withString: @""];
+      else
+	[keysWithFormat replaceString: [keys objectAtIndex: count]
+			withString: [value description]];
     }
 
   return keysWithFormat;