[metapost] a problem of label when using metapost

[source liu]

Hi all,

it has been quite a few years since i picked up, but i've picked up
metapost just for a short time.

It works almost right,  except for the case i want to insert label.

I'm sure the problem lies in it,  for i comment the label line, it
layout the exact figure i want to get(
without text of course).

1.  TeX
when it comes to the first line of
-------------------------------------------
label.top(btex *somethinghere* etex, z1)
-------------------------------------------

it would be fine,  but the situation changes when a second similar
label is invoking as above.

the error message is always be something like , >> mpx file can't be create.

2. LaTeX

it is said that one can changed the defaut TeX system by placing
%&latex at the beginning.

yet, it is true, except for it works not the same as i found through
the internet, which i found
%&latex is after vebatimtex,

such as
-----------------------------------------
vebatimtex
   %&latex
*something else here*

etex
-----------------------------------------


is not work for me, 'cause it not recognize the \documentstyle command
 but
----------------------------------------
%&latex
verbatimtex
*something else here*

etex
---------------------------------------
works,  though with error message
"/somedir/.texmf/tex/latex/latex.fmt. is not an latex mem file"

still failed to generate label.


Any suggestion on this, or has someone involved the same problem as well as me?

My TeX system is TeXLive 2010,  got it from the apt source of debian,
without any specific configure for
myself.


best regards.



BTW, is there any way to change the displayed name of myself in the
maillist,  i clicked applied before i
realized that i left my email address as displayed name.


Thanks so much.

-- 
Liu An
Institution of modern physics, Shanghai, China