Error while AUTOSAR Code generation

Hello, I get the following error while generating AUTOSAR compliant code in MATLAB 2013b. Error: File: C:\Program Files (x86)\MATLAB\R2013b\rtw\c\tlc\mw\opaquelib.tlc Line: 947 Column: 3 Unable to find ExternalInputArgDef within the Interface scope

I have narrowed down this error to one particular merge block. In my model I have outputs coming from different functions executing at different time and I merge the Outputs. It works fine for rest 7 cases only for one merge it gives this error.

Kindly let me know if anyone else has faced a similar issue. Thanks.