Script task runtime error

I have a script task which when I try to execute I get the following popup error messagebox (I cannot even debug the task, no breakpoints are reached even if its the first line):

DTS Script task has encountered an exception in user code

Exception has been thrown by the target of an invocation.

at System.RuntimeMethodHandle._InvokeMethodFast(IRuntimeMethodInfo method, Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeType typeOwner)

   at System.RuntimeMethodHandle.InvokeMethodFast(IRuntimeMethodInfo method, Object target, Object[] arguments, Signature sig, MethodAttributes methodAttributes, RuntimeType typeOwner)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at System.RuntimeType.InvokeMember(String name, BindingFlags bindingFlags, Binder binder, Object target, Object[] providedArgs, ParameterModifier[] modifiers, CultureInfo culture, String[] namedParams)
   at Microsoft.SqlServer.Dts.Tasks.ScriptTask.VSTATaskScriptingEngine.ExecuteScript()

Now - heres the thing.  I have copied the code from inside the script task and transferred it over to a C# windows form project, so the code gets executed when a button gets clicked.  It works fine!  Why is the exact same code not getting executed in SSIS?

I have hardcoded all the variables in the script task for now, I am not passing in any variables.