diff --git a/.DS_Store b/.DS_Store
deleted file mode 100644
index 4e47e72..0000000
Binary files a/.DS_Store and /dev/null differ
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..00b41c6
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+bin/
+.DS_Store
diff --git a/VersionChecker/.DS_Store b/VersionChecker/.DS_Store
deleted file mode 100644
index 1901893..0000000
Binary files a/VersionChecker/.DS_Store and /dev/null differ
diff --git a/VersionChecker/src/versionchecker/actions/VCArtifactTable.java b/VersionChecker/src/versionchecker/actions/VCArtifactTable.java
index ad3ae73..a7b0782 100644
--- a/VersionChecker/src/versionchecker/actions/VCArtifactTable.java
+++ b/VersionChecker/src/versionchecker/actions/VCArtifactTable.java
@@ -84,11 +84,15 @@ public void mouseClicked(MouseEvent e) {
 	}
 
 	public String getSelectedID() {
-		return this.selectedAF.getId();
+		if (this.selectedAF != null)
+			return this.selectedAF.getId();
+		return null;
 	}
 
 	public String getSelectedVer() {
-		return this.selectedAF.getVersion();
+		if (this.selectedAF != null)
+			return this.selectedAF.getVersion();
+		return null;
 	}
 
 	private void addEntry(VCArtifact toAdd) {
diff --git a/VersionChecker/src/versionchecker/actions/VCMainWindow.java b/VersionChecker/src/versionchecker/actions/VCMainWindow.java
index d660cd9..cce5bdc 100644
--- a/VersionChecker/src/versionchecker/actions/VCMainWindow.java
+++ b/VersionChecker/src/versionchecker/actions/VCMainWindow.java
@@ -11,6 +11,7 @@
 import javax.swing.BoxLayout;
 import javax.swing.JButton;
 import javax.swing.JFrame;
+import javax.swing.JOptionPane;
 import javax.swing.JPanel;
 import javax.swing.JTextField;
 
@@ -120,7 +121,10 @@ public void actionPerformed(ActionEvent event) {
 		fetchButton.addActionListener(new ActionListener() {
 			public void actionPerformed(ActionEvent event) {
 				String id = tablePanel.getSelectedID();
-				VCCloneTask task = new VCCloneTask(id,null);
+				if (id != null)
+					new VCCloneTask(id,null);
+				else
+					JOptionPane.showMessageDialog(null, "No component is selected.", "VersionChecker", 1);;
 			}
 		});
 		
@@ -128,7 +132,10 @@ public void actionPerformed(ActionEvent event) {
 			public void actionPerformed(ActionEvent event) {
 				String id = tablePanel.getSelectedID();
 				String ver = tablePanel.getSelectedVer();
-				VCCloneTask task = new VCCloneTask(id,ver);
+				if (id != null)
+					new VCCloneTask(id,ver);
+				else
+					JOptionPane.showMessageDialog(null, "No component is selected.", "VersionChecker", 1);;
 			}
 		});