Index: dbitem.php
===================================================================
--- dbitem.php	(revision 13274)
+++ dbitem.php	(working copy)
@@ -226,7 +226,7 @@
 				$this->FieldErrors[$error_field]['value'] = $error_params['value'];
 				unset($error_params['value']);
 			}
-			
+
 			// additional params, that helps to determine error sources
 			$this->FieldErrors[$error_field]['params'] = $error_params;
 		}
@@ -450,7 +450,15 @@
 
 		// 2. don't write empty field value to db, when "skip_empty" option is set
 		$field_value = array_key_exists($field_name, $this->FieldValues) ? $this->FieldValues[$field_name] : false;
-		$skip_empty = array_key_exists('skip_empty', $this->Fields[$field_name]) ? $this->Fields[$field_name]['skip_empty'] : false;
+
+		if (array_key_exists($field_name, $this->Fields)) {
+			$skip_empty = array_key_exists('skip_empty', $this->Fields[$field_name]) ? $this->Fields[$field_name]['skip_empty'] : false;
+		}
+		else {
+			// field found in database, but not declared in unit config
+			$skip_empty = false;
+		}
+
 		$skip = $skip || (!$field_value && $skip_empty);
 
 		// 3. skipping field not in Fields (nor virtual, nor real)