title: InternalCompilerError when I import the new Facebook 5.1 SDK into my existing project
body: <p>If I import this package in a new project, I get no problems at all.</p>
  
  <p>But, when I try to import it into my existing project (that had the 5.0.4 version of the SDK), after the importing finished, I get the followin error message:</p>
  
  <pre><code>Unhandled Exception: Mono.CSharp.InternalErrorException: Internal error
  
    at Mono.CSharp.MethodGroupExpr.IsApplicable (Mono.CSharp.ResolveContext ec, Mono.CSharp.Arguments&amp; arguments, Int32 arg_count, System.Reflection.MethodBase&amp; method, System.Boolean&amp; params_expanded_form) [0x00000] in &lt;filename unknown&gt;:0 
  
    at Mono.CSharp.MethodGroupExpr.OverloadResolve (Mono.CSharp.ResolveContext ec, Mono.CSharp.Arguments&amp; Arguments, Boolean may_fail, Location loc) [0x00000] in &lt;filename unknown&gt;:0 
  
    at Mono.CSharp.Invocation.DoResolveOverload (Mono.CSharp.ResolveContext ec) [0x00000] in &lt;filename unknown&gt;:0 
  
    at Mono.CSharp.Invocation.DoResolve (Mono.CSharp.ResolveContext ec) [0x00000] in &lt;filename unknown&gt;:0 
  
    at Mono.CSharp.Expression.Resolve (Mono.CSharp.ResolveContext ec, ResolveFlags flags) [0x00000] in &lt;filename unknown&gt;:0 
  
    at Mono.CSharp.Expression.Resolve (Mono.CSharp.ResolveContext ec) [0x00000] in &lt;filename unknown&gt;:0 
  
    at Mono.CSharp.ExpressionStatement.ResolveStatement (Mono.CSharp.BlockContext ec) [0x00000] in &lt;filename unknown&gt;:0 
  
    at Mono.CSharp.StatementExpression.Resolve (Mono.CSharp.BlockContext ec) [0x00000] in &lt;filename unknown&gt;:0 
  
    at Mono.CSharp.Block.Resolve (Mono.CSharp.BlockContext ec) [0x00000] in &lt;filename unknown&gt;:0 
  
    at Mono.CSharp.ToplevelBlock.Resolve (Mono.CSharp.FlowBranching parent, Mono.CSharp.BlockContext rc, Mono.CSharp.ParametersCompiled ip, IMethodData md) [0x00000] in &lt;filename unknown&gt;:0 
  </code></pre>
  
  <p>Anyone have any idea why this is happening?</p>
  
  <p>(As extra information, in my project I have Itween &amp; EasyTouch integrated)</p>