Here is a reasonable guess. Switch is really a source filter - it attempts to rewrite your program for you. I'm betting that unless you fix the bug in Switch you probably shouldn't use it here. Be sure to file your bug report at http://rt.cpan.org/NoAuth/Bugs.html?Dist=Switch.

Switch.pm: BUGS
There are undoubtedly serious bugs lurking somewhere in code this funky :-) Bug reports and other feedback are most welcome.