Can't solve your problem, but for what it's worth it does fail properly on my OS X system. Interestingly though, if I call it like you did with an argument to the non-existent program, *that* error is raised first: 

[502]► perl -E'
open ( FOO, "-|", "caesar" ) or die $!;
'
No such file or directory at -e line 2.

[503]► perl -E'
open ( FOO, "-|", "caesar <article" ) or die $!;
'
sh: article: No such file or directory

[download]

The way forward always starts with a minimal test.

In reply to Re: Capturing errors from 3-arg pipe open in ActivePerl 5.020 by 1nickt
in thread [SOLVED] Capturing errors from 3-arg pipe open in ActivePerl 5.020 by ateague

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