SSIS Connection not found in package

I'm a little late to the party, but I ran across this thread while experiencing the same errors and found a different resolution.

When creating an SSIS 2012 package, in the Solution Explorer window you will see the Connection Managers folder at the project level. This seems like the most logical place to create a connection, and should be used when creating a connection that can be used by any package in the project. It is included at the project level, and not the package level.

When running my dtsx package using dtexec, I received the same errors shown above. This is because the connection is not included in the package (just the project). My solution was to go into the package designer, and then in the Connection Manager window, right click the project level connection (which is shown using the "(project)" prefix) and choose "Convert to Package Connection". This will embed the connection in the actual dtsx package. This alleviated my problem.

It seems that your ssis package is pointing to some other connection which might have been deleted or renamed .Try opening the SSIS compoenents and point to the correct connection which are there in your connection manager .

It happens when we copy the SSIS package components to create a new package or because of renaming the connections or there may be still components which are using the old connection defined in you xml config file( In your case try checking the Execute SQL Task which is throwing error ) .If you are using XML for configuration try deploying the new one.