diff --git a/src/main/java/org/gcube/portlets/user/td/expressionwidget/client/ConditionWidget.java b/src/main/java/org/gcube/portlets/user/td/expressionwidget/client/ConditionWidget.java
index e804384..4fb8dd3 100644
--- a/src/main/java/org/gcube/portlets/user/td/expressionwidget/client/ConditionWidget.java
+++ b/src/main/java/org/gcube/portlets/user/td/expressionwidget/client/ConditionWidget.java
@@ -410,7 +410,7 @@ public class ConditionWidget extends SimpleContainer {
 		comboOp.setTriggerAction(TriggerAction.ALL);
 
 		horiz.add(comboOp, new BoxLayoutData(new Margins(0)));
-		if (column==null|| column.getDataTypeName().compareTo("Date") != 0) {
+		if (column==null|| column.getDataTypeName()==null|| column.getDataTypeName().compareTo("Date") != 0) {
 			horiz.add(firstArg, new BoxLayoutData(new Margins(0)));
 			horiz.add(andText, new BoxLayoutData(new Margins(0)));
 			horiz.add(secondArg, new BoxLayoutData(new Margins(0)));
diff --git a/src/main/java/org/gcube/portlets/user/td/expressionwidget/client/ReplaceColumnByExpressionDialog.java b/src/main/java/org/gcube/portlets/user/td/expressionwidget/client/ReplaceColumnByExpressionDialog.java
index 1f34fa6..e2c5679 100644
--- a/src/main/java/org/gcube/portlets/user/td/expressionwidget/client/ReplaceColumnByExpressionDialog.java
+++ b/src/main/java/org/gcube/portlets/user/td/expressionwidget/client/ReplaceColumnByExpressionDialog.java
@@ -214,9 +214,11 @@ public class ReplaceColumnByExpressionDialog extends Window implements
 							ColumnTypeCode.TIMEDIMENSION.toString()) == 0) {
 				removableColumn.add(c);
 			} else {
-				if (c.getColumnId() != null
+				if (c.getColumnId() != null && column != null
+						&& column.getColumnId() != null
+						&& !column.getColumnId().isEmpty()
 						&& c.getColumnId().compareTo(column.getColumnId()) == 0) {
-					column=c;
+					column = c;
 				}
 			}
 		}
diff --git a/src/main/java/org/gcube/portlets/user/td/expressionwidget/client/ReplaceColumnByExpressionPanel.java b/src/main/java/org/gcube/portlets/user/td/expressionwidget/client/ReplaceColumnByExpressionPanel.java
index 9ec337c..7a9012c 100644
--- a/src/main/java/org/gcube/portlets/user/td/expressionwidget/client/ReplaceColumnByExpressionPanel.java
+++ b/src/main/java/org/gcube/portlets/user/td/expressionwidget/client/ReplaceColumnByExpressionPanel.java
@@ -136,7 +136,7 @@ public class ReplaceColumnByExpressionPanel extends FramedPanel {
 	}
 
 	protected void calcHeight() {
-		if (column != null
+		if (column != null && column.getDataTypeName()!=null && !column.getDataTypeName().isEmpty()
 				&& (column.getDataTypeName().compareTo(
 						ColumnDataType.Text.toString()) == 0
 						|| column.getDataTypeName().compareTo(
@@ -307,7 +307,7 @@ public class ReplaceColumnByExpressionPanel extends FramedPanel {
 		VerticalLayoutContainer replaceValueFieldSetLayout = new VerticalLayoutContainer();
 		replaceValueFieldSet.add(replaceValueFieldSetLayout);
 
-		if (column == null) {
+		if (column == null || column.getDataTypeName()==null ||column.getDataTypeName().isEmpty()) {
 			replaceValue = new TextField();
 			replaceValue.setToolTip("Replace Value");
 			replaceValue.setValue("");
@@ -361,17 +361,18 @@ public class ReplaceColumnByExpressionPanel extends FramedPanel {
 	}
 
 	protected void setSelectedColumn() {
-		if (column == null) {
+		if (column == null|| column.getTypeCode()==null) {
 
 		} else {
+			
 			ColumnTypeCode typeCode = ColumnTypeCode
 					.getColumnTypeCodeFromId(column.getTypeCode());
 			HTML errorMessage;
 			if (typeCode == null) {
 				errorMessage = new HTML(
-						"This column has column data type null!");
+						"This column has column type code null!");
 				UtilsGXT3.alert("Error",
-						"This column has column data type null!!");
+						"This column has column type code null!!");
 				return;
 			}