If I understood your question correctly, this should do the trick. I've modified your input data (only to make it consistantly spaces; you could change it back) and fixed your regex. When doing an or (||) or an and (&&), you need to specify what to compare it to every time (ex/ $foo =~ /$bar/ || $foo =~ /$bor/ || ...). Instead of doing this, I've done it in the regex.

while (<DATA>) {
    print unless /(Everyone\s+R X|Webmins\s+all|Domain Admins\s+all|\s
++o\s*\z)/;
}

__DATA__
wwwroot\development\images\_notes\homepage_area_68_f4.jpg.mno   Everyo
+ne                R X
wwwroot\development\images\_notes\homepage_area_68_f4.jpg.mno   Domain
+\Webmins          RWXD
wwwroot\development\images\_notes\homepage_area_68_f4.jpg.mno   Domain
+\Domain Admins    all
wwwroot\development\images\_notes\homepage_area_68_f4.jpg.mno   Domain
+\user             o
[download]

That outputs

wwwroot\development\images\_notes\homepage_area_68_f4.jpg.mno   Domain
+\Webmins          RWXD
[download]

which I assume is what you want?