From looking at the source, and the location of the error message, it seems that Proc::Background makes the error of checking $ENV{PATH} for the program, but fails to know that the current directory on Windows is implied to be on the path.

Maybe you can check whether prefixing your Perl script with the current directory works?

$proc = Proc::Background->new("./bg_script.pl $ARG1 $ARG2 $ARG3 $ARG4"
+);

[download]
or 
$proc = Proc::Background->new(".\\bg_script.pl $ARG1 $ARG2 $ARG3 $ARG4
+");

[download]

In reply to Re: Using Proc::Background and Win32 by Corion
in thread Using Proc::Background and Win32 by mmartin

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.