diff --git a/src/main/java/org/gcube/portlets/user/td/expressionwidget/client/ColumnExpressionPanel.java b/src/main/java/org/gcube/portlets/user/td/expressionwidget/client/ColumnExpressionPanel.java
index 34f3bb7..ac3e8ec 100644
--- a/src/main/java/org/gcube/portlets/user/td/expressionwidget/client/ColumnExpressionPanel.java
+++ b/src/main/java/org/gcube/portlets/user/td/expressionwidget/client/ColumnExpressionPanel.java
@@ -374,14 +374,18 @@ public class ColumnExpressionPanel extends FramedPanel {
 		comboAttributeType.setTriggerAction(TriggerAction.ALL);
 
 		if (initialRuleDescriptionData != null) {
+			Log.debug("Initial RuleDescriptionData: "+initialRuleDescriptionData);
 			ColumnDataType cdt = retrieveColumnDataType();
 			if (cdt != null) {
+				Log.debug("Retrieved column data type: "+cdt);
 				ColumnDataTypeElement cdte = ColumnDataTypeStore
 						.selectedAttributeElement(cdt);
 				if (cdte != null) {
 					comboAttributeType.setValue(cdte);
 
 				}
+			} else {
+				Log.debug("Retrieved column data type null");
 			}
 		}
 
diff --git a/src/main/java/org/gcube/portlets/user/td/expressionwidget/client/ReplaceExpressionDialog.java b/src/main/java/org/gcube/portlets/user/td/expressionwidget/client/ReplaceExpressionDialog.java
index 49183a5..f7688b1 100644
--- a/src/main/java/org/gcube/portlets/user/td/expressionwidget/client/ReplaceExpressionDialog.java
+++ b/src/main/java/org/gcube/portlets/user/td/expressionwidget/client/ReplaceExpressionDialog.java
@@ -86,6 +86,7 @@ public class ReplaceExpressionDialog extends Window implements
 		this.eventBus = eventBus;
 		this.trId=trId;
 		column = new ColumnData();
+		column.setId(columnMockUp.getId());
 		column.setColumnId(columnMockUp.getColumnId());
 		column.setLabel(columnMockUp.getLabel());
 		column.setDataTypeName(columnMockUp.getColumnDataType().toString());
@@ -112,19 +113,25 @@ public class ReplaceExpressionDialog extends Window implements
 		listeners=new ArrayList<ExpressionWrapperNotificationListener>();
 		this.eventBus = eventBus;
 		column = new ColumnData();
+		column.setId(columnMockUp.getId());
 		column.setColumnId(columnMockUp.getColumnId());
 		column.setLabel(columnMockUp.getLabel());
 		column.setDataTypeName(columnMockUp.getColumnDataType().toString());
 		column.setTypeCode(columnMockUp.getColumnType().toString());
+		Log.debug("ReplaceExpressionDialog: Column: "+column);
 		
 		columns=new ArrayList<ColumnData>();
+		Log.debug("ReplaceExpressionDialog Columns:");
 		for(ColumnMockUp colMock:columnMockUpList){
 			ColumnData col = new ColumnData();
+			col.setId(colMock.getId());
 			col.setColumnId(colMock.getColumnId());
 			col.setLabel(colMock.getLabel());
 			col.setDataTypeName(colMock.getColumnDataType().toString());
 			col.setTypeCode(colMock.getColumnType().toString());
+			Log.debug("Columns: "+col);
 			columns.add(col);
+			
 		}
 		
 		type = ReplaceExpressionType.Template;
diff --git a/src/main/java/org/gcube/portlets/user/td/expressionwidget/client/expression/ReplaceWidget.java b/src/main/java/org/gcube/portlets/user/td/expressionwidget/client/expression/ReplaceWidget.java
index 8521c46..4efb768 100644
--- a/src/main/java/org/gcube/portlets/user/td/expressionwidget/client/expression/ReplaceWidget.java
+++ b/src/main/java/org/gcube/portlets/user/td/expressionwidget/client/expression/ReplaceWidget.java
@@ -290,7 +290,7 @@ public class ReplaceWidget extends SimpleContainer {
 				propsColumnData.id());
 		Log.debug("Store Columns: " + storeColumns);
 		storeColumns.addAll(columns);
-
+		
 		final ComboBox<ColumnData> comboColumns = new ComboBox<ColumnData>(
 				storeColumns, propsColumnData.label());
 
diff --git a/src/main/java/org/gcube/portlets/user/td/expressionwidget/server/ExpressionServiceImpl.java b/src/main/java/org/gcube/portlets/user/td/expressionwidget/server/ExpressionServiceImpl.java
index dd7a668..bbca014 100644
--- a/src/main/java/org/gcube/portlets/user/td/expressionwidget/server/ExpressionServiceImpl.java
+++ b/src/main/java/org/gcube/portlets/user/td/expressionwidget/server/ExpressionServiceImpl.java
@@ -305,6 +305,7 @@ public class ExpressionServiceImpl extends TDGWTServiceImpl implements
 						ruleDescription.getOwner(),
 						RuleScopeMap.map(ruleDescription.getScope()),
 						tdRuleColumnType, cexp);
+				logger.info("Rule: "+ruleData);
 				rulesDes.add(ruleData);
 
 			}
@@ -357,7 +358,12 @@ public class ExpressionServiceImpl extends TDGWTServiceImpl implements
 
 			List<RuleDescription> rules = service
 					.getApplicableBaseColumnRules(dataType);
-
+			if(rules==null){
+				logger.error("Invalid applicable base column rules from service: null");
+				throw new TDGWTServiceException("Error retrieving the rules: invalid applicable base column rules from service(null)");
+			} else {
+				logger.debug("Applicable Base Column Rules: "+rules.size());
+			}
 			ArrayList<RuleDescriptionData> rulesDes = new ArrayList<RuleDescriptionData>();
 
 			C_ExpressionParser parser = new C_ExpressionParser();
@@ -374,6 +380,7 @@ public class ExpressionServiceImpl extends TDGWTServiceImpl implements
 						RuleScopeMap.map(ruleDescription.getScope()),
 						tdRuleColumnType, cexp);
 				rulesDes.add(ruleData);
+				logger.info("Rule:"+ruleData);
 
 			}
 
@@ -387,7 +394,7 @@ public class ExpressionServiceImpl extends TDGWTServiceImpl implements
 			e.printStackTrace();
 			throw e;
 		} catch (Throwable e) {
-			logger.error("Error in getRule(): " + e.getLocalizedMessage());
+			logger.error("Error in getApplicableBaseColumnRules(): " + e.getLocalizedMessage());
 			e.printStackTrace();
 			throw new TDGWTServiceException("Error retrieving the rules: "
 					+ e.getLocalizedMessage());
@@ -428,7 +435,11 @@ public class ExpressionServiceImpl extends TDGWTServiceImpl implements
 
 			RuleColumnType ruleColumnType = RuleColumnTypeMap
 					.map(ruleDescriptionData.getTdRuleColumnType());
-
+			if(ruleColumnType==null){
+				logger.debug("Error saving rule: rule column type is null!");
+				throw new TDGWTServiceException("Error saving rule: rule column type is null!");
+			}
+			
 			RuleId ruleId = service.saveColumnRule(
 					ruleDescriptionData.getName(),
 					ruleDescriptionData.getDescription(), conditionExpression,