diff --git a/gui/Gui/Error.py b/gui/Gui/Error.py
new file mode 100644
index 0000000..8916b7e
--- /dev/null
+++ b/gui/Gui/Error.py
@@ -0,0 +1,21 @@
+#!/usr/bin/python
+
+#---------------------------------------------------------------------------
+
+""" Import externals """
+import wx
+import sys
+
+#---------------------------------------------------------------------------
+
+""" Import scyther-gui components """
+
+#---------------------------------------------------------------------------
+
+def ShowAndExit(text):
+    title = "Error"
+    dlg = wx.MessageDialog(None, text, title, wx.ID_OK | wx.ICON_ERROR)
+    result = dlg.ShowModal()
+    dlg.Destroy()
+    sys.exit()
+
diff --git a/gui/Scyther/Error.py b/gui/Scyther/Error.py
new file mode 100644
index 0000000..c512163
--- /dev/null
+++ b/gui/Scyther/Error.py
@@ -0,0 +1,49 @@
+#!/usr/bin/python
+#
+# Scyther interface error classes
+#
+
+#---------------------------------------------------------------------------
+
+class Error(Exception):
+    """Base class for exceptions in this module."""
+    pass
+
+class InputError(Error):
+    """Exception raised for errors in the input.
+
+    Attributes:
+        expression -- input expression in which the error occurred
+        message -- explanation of the error
+    """
+
+    def __init__(self, expression, message):
+        self.expression = expression
+        self.message = message
+
+class BinaryError(Error):
+    """Raised when the Scyther executable is not found.
+
+    Attributes:
+        file -- file location at which we should have been able to find it.
+    """
+
+    def __init__(self, file):
+        self.file = file
+
+    def __str__(self):
+        return "Could not find Scyther executable at '%s'" % (self.file)
+
+
+class UnknownPlatformError(Error):
+    """Raised when the platform is not supported yet.
+
+    Attributes:
+        platform -- string describing the platform.
+    """
+
+    def __init__(self, platform):
+        self.platform = platform
+
+    def __str__(self):
+        return "The %s platform is currently unsupported." % self.platform