hm, not here
>From texlive 2008
#> texexec  --pdfarrange  --result=test.pdf test001.pdf test012.pdf
test002.pdf
/opt/TeXLive2008/texlive/2008/bin/i386-linux/texmfstart:1755: warning:
Insecure world writable dir /opt/luatex/minimals-beta in PATH, mode 040777
/opt/TeXLive2008/texlive/2008/texmf-dist/scripts/context/ruby/base/system.rb:16:
warning: Insecure world writable dir /opt/luatex/minimals-beta in PATH, mode
040777
TeXExec | arranging file test001.pdf
TeXExec | arranging file test012.pdf
TeXExec | arranging file test002.pdf

If I add --sort

# texexec  --pdfarrange --sort --result=test.pdf test001.pdf test012.pdf
test002.pdf
/opt/TeXLive2008/texlive/2008/bin/i386-linux/texmfstart:1755: warning:
Insecure world writable dir /opt/luatex/minimals-beta in PATH, mode 040777
/opt/TeXLive2008/texlive/2008/texmf-dist/scripts/context/ruby/base/system.rb:16:
warning: Insecure world writable dir /opt/luatex/minimals-beta in PATH, mode
040777
TeXExec | arranging file test001.pdf
TeXExec | arranging file test002.pdf
TeXExec | arranging file test012.pdf
TeXExec | processing document 'texexec

# texexec --check
/opt/TeXLive2008/texlive/2008/bin/i386-linux/texmfstart:1755: warning:
Insecure world writable dir /opt/luatex/minimals-beta in PATH, mode 040777
/opt/TeXLive2008/texlive/2008/texmf-dist/scripts/context/ruby/base/system.rb:16:
warning: Insecure world writable dir /opt/luatex/minimals-beta in PATH, mode
040777
TeXExec | current distribution: web2c
TeXExec | context source date: 2008.05.21 15:21
:
:
TeXExec |
TeXExec | TeXExec | version 6.2.0 - 1997-2006 - PRAGMA ADE/POD
TeXExec | TeXUtil   | version 9.1.0 - 1997-2005 - PRAGMA ADE/POD
TeXExec | CtxTools | version 1.3.5 - 2004/2008 - PRAGMA ADE

-- 
luigi