Try putting your code into <code> blocks... like this:

use Error qw(:try); 
try { 
`$create_script $input`; #code that might thrown an exception; 
return; 
} catch Error with { 
my $error_handler = shift; # Get hold of the exception object 
} 

exit;
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As it is, I don't see any "syntax" errors with that. However:

1) There is no need to "return" from the try block
2) No output will be captured.

If you want the actual output from the script captured, do this:
my $output = `$create_script $input`

If you want the return code, you need to check out the system call.