[Javascript] error when sending form

[javascript@xxxxxxxxxx (Manuel Socarras Reyes)]

hi:

a friend asked me to test a page he's doing containing a very long form 
and submitted via email:

<FORM method="POST" action="mailto:xxx@xxxxxxx"; enctype="text/plain">

in IE 5 / Mac it seems to work fine but in NN 4.78 / Mac i received this 
error:
 
"An error ocurred while sending mail. The mail server responded: Data 
line too long (Max 1024)"

it seems the source of the problem is the lenght of the form but i'd 
expected that with GET method, not with POST. any idea?

TIA,

-- 
Saludos,

Manuel Socarrás Reyes <msocarras@xxxxxxxx>
Barcelona. Spain