You are not defining an anonymous sub, you are trying to call a subroutine with the name generated from the block: 
&{ 
   # code here returns a value,
   # that's interpreted as the name
   # of the subroutine to call...
 }

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You need something like: 

my $subroutine = sub {
     # code here defines an anonymous sub
};

$subroutine->( @arguments ); #call sub

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You should ask yourself what you want to do with your example: do you want to define a subroutine, call it or both?

In your case, I would just use an unless statement: 

unless ($newSeriesSth->execute()) {
   # error handling
}

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Anonymous subs (esp. closures) are of much more use when you need callbacks. 
-- 
Joost       downtime n. The period during which a system
            is error-free and immune from user input.

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In reply to Re: Anonymous sub as error handler by Joost
in thread Anonymous sub as error handler by CubicSpline

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