(clutching at straws...)
One thing worth checking: try changing the tilde (~) to something else (eg 'x'), just in case it is being interpreted as a special character. It does have a special meaning in C# (which is what the SSIS expression language appears loosely based on).
If you haven't even tried to resolve your issue, please don't expect the hard-working volunteers here to waste their time providing links to answers which you could easily have found yourself.